I think the reason that so many people have a problem with this is pretty simple. Had this show opened in 1986 and had a healthy run of four or five years it would have been a different story. The show would've closed and those of us lucky enough to see the original production would forever have fond memories of it.
Then, maybe a revival would've been mounted 20 or 25 years later. A whole new generation of theatergoers would experience it for the first time. Potentially, the producers could've completely reimagined the show and new audiences probably would've embraced it. Chances are, it would've been not nearly as opulent as the original production...but to a new generation of audience, this probably would not have mattered. I say this because pared down revivals have been loved by people who never saw the original production (and some who have).
If you saw the original productions of FOLLIES, SWEENEY TODD, ON THE TWENTIETH CENTURY, SUNSET BLVD and more, you would understand how scaled back some of these newer revivals have been. If you didn't see the original productions, these shows were fairly "new" to you by the time the revivals came along.
PHANTOM OF THE OPERA has been running for 35 years. Most of us that have seen the show, saw an iteration of it that's comparable to the original production...for the most part. That is why when drastic changes are announced for a show that is still running, or fresh in all of our minds, it is met with such aversion. We've had a year of lockdown and now this PHANTOM, which we're ALL familiar with (or the overwhelming majority of us are) is being tampered with. It's done ALL the time...but usually after a show has been out of the public conscience for enough time.
Some of us on this board feel like a lot of you are feeling about POTO...but we felt that way about the revivals of FOLLIES, SWEENEY TODD, ON THE TWENTIETH CENTURY, SUNSET BLVD and more.