Musical or Machine?

Deep stuff.

Yes, I think it's theatre. It's very commmercial theatre, but theatre and unprecedented in many ways. Your points are valid, but keep in mind that the decade+ run is rather rare these days, and also rather new in the overall scheme of things in the history of theatre. It certainly did not exist to this level pre-Mackintosh/Webber era, and it's rare that it does now with contemporary shows sans Wicked and Chicago.

I think the key here is quality, and I think for shows like Les Mis, Phantom and Wicked, there's diffidently a great deal of quality control. I purposely left out Chicago. But quality control is the key word and other business jargon is applicable..yes it's art, but it's also business and the perfect marriage of art to create a profitable business.

Interestingly, the whole premise of Mackintosh revamping his shows is to bring a new spin and spirit to otherwise iconic pieces that are too sacrosanct to reproduce in another format. While I truly think that his case is more of a business case than an artistic one, I think it addresses some of your concerns about it being more machine than musical.

For the first people that see a show even in its 17th year it is opening night. Of course it is still theatre!!! Just a very successful show that has an open ended run do to popular ticket sales. In this social media age shows can become cult hits online such as Hamilton or Harry Potter and these become multi billion dollar hits and huge brands. Lion King is another example. 7.6 billion dollars later - it is still theatre.

The mistake in the original premise of this thread, in my opinion, is that it takes into account neither cast nor audience.

Even for a show that is 30 years old, the vast majority of the audience seeing it at each performance will be seeing it for the first time. So the show is as much theatre to them as any show is the first time you see it - the length the show has run makes no difference whatsoever to that.

And the cast changes fairly frequently in any show. Yes, some people may stay for years, but each year you will have a group of people who are completely new to the material, or returning to it after a break in some cases, putting their own spin on it. Take Wicked, for example - every Glinda puts their own quirks and mannerisms into Popular, and some even change their performance over the course of their run. I don't see how that is any less theatre than the cast of a new work exploring it for the first time, and it's a bit offensive towards new casts to essentially suggest they're incapable of bringing any creativity to established roles. The only difference is that there are example performances to look back on where a show is a long-runner, but that doesn't dictate how any individual plays the role. If it did, Hamlet would have been played exactly the same for nearly half a millennium, but it hasn't been.

I personally think it's a little snobbish to think that only new work is theatre and that the older works have less value. Sometimes they're much better and more entertaining than some of the rubbish churned out today, much like a lot of classical music, which has also stood the test of time. It's all a matter of opinion in the end as to whether long runners are a good thing (and not all long runners may be the same in that regard), but it's a matter of fact that they are all theatrical works.

Perhaps not, but it is musically creative, and probably on occasion improvisational and responsive to the moment.

It's not a matter of capability, it's a matter of permission.

It depends how much input the original cast had into the characterisation. But is there really any significant difference? To use Phantom as an example, is there any real difference between a new Phantom being directed by the original instructions handed down from cast to cast and a new Phantom being given the same instructions directly by the director of a new production?

I disagree. Using the Phantom example, current Phantom, Ben Forster's interpretation of the character is wildly different from Michael Crawford's. Crawford's Phantom was a broken man, a genius but a man purely motivated and obsessed with love. Ben Forster has taken upon his performance a real emphasis of the mental distortion of the character, this can be seen by his repeated head hitting during the final lair scene amongst other differences. As if to denote a tick that someone with real mental issues might have. This is a characterisation I personally disagree with and as a result really don't like BF's interpretation of the Phantom.
Furthermore in the ~20 years I've been seeing this show up until around 2 years ago I really disliked the character Raoul. No matter who played him, I didn't like the character. This changed when I saw Nadim Naaman's Raoul in the current cast. Nadmin brings an innocence that I've not ever seen in Raoul before. The bolshy-ness is toned down and at points he shows an empathy to the Phantom that most actors exchange a bravado for.

Its interesting that two notable changes to two principal characters has happened during the same cast, but had these actors been playing carbon copies of the original cast then these interpretations wouldn't be seen in their roles. 

There isn't a production of any Shakespeare play that's been running for a decade though is there?

And, just to note, I'm not seeking agreement. I was posing a question in my original post. I'm late to the party, if these productions had closed after a year or even 5 years I would never have seen them. I wasn't questioning whether they should be on, I wouldn't deny audiences from seeing them. I just wonder if theyve become something other than theatre.

Was that cut down version of POTO in Vegas theatre? Or was it an 'entertainment' of some sort?

I often see touring shows that I think are "ok" then I immediately forget about. Months later I hear they're at the other end of the country and am amazed they are still doing this show, almost every day, every week but in a different part of the country each week. I struggle to imagine how they stay so motivated and how they still make the shows look so fresh night after night after night when they must be bored to pieces of it.

Things also evolve...Mme Thenardier for example. The character is now a far cry from the slim, darkly nuanced humour of Sue Jane Tanner to the hugely corpulent pantomime caricature a couple of years back.

West End is a vast landscape of theatres that has room for traditional shows and good new shows. My contention isn't about getting rid of old shows, that have put millions into the economy and provided stable work for ACTORS and theatre staff.

With the population set to grow from 8.2m to 10m by 2030, there is a good strong argument that the Weat End could do with more new theatres. I would argue for a couple of mid-size houses like they have on Broadway, however build better more comfortable theatres unlike Broadway and more like personal favourites of mine the Lowry of the Wales Milenium Centre, this is what London needs!!!

Theatre is always an act of repetition in some form - whether it's a week's run on the fringe, or 10 years in the West End. The quality of that repetition is to do with the people involved, not the length of the run.