Agreed - I'm 25 and a massive supporter of the classics. I recognize their value and uniqueness. While I appreciate the Disney media I grew up with, and do enjoy their presence in the Parks, there needs to be a balance. I'm more impressed by an original idea, like PoTC or the original EPCOT Center dark rides, than I am of anything media IP-related that's opened in the Parks during my lifetime. And it's not even just "boring" rides - Everest is a more engaging experience to me than something like Tron or GotG (which I won't deny is a great coaster). I've been engaged with EPCOT Center lore, for example, since I was 10 - I took my profile picture when I was like 13 because I was enamored by the history of the Imagination Pavilion.
TWDC is not solely pushing its IP mandate because "it's what people like" - clearly people "like" Marvel, Princesses, Star Wars (arguable, not opening that can here), Pixar, and all of the the other media Disney puts out. But they clearly also like Park original ideas. As it stands, that's the issue though; there is no balance. It's just a deluge of attractions ONLY based on media IP. And anyone who makes the argument for the removal of TSI and ROA under the pretense "people's interests have changed since the 50s", the same thing can be applied to ALL of the IP-specific attractions and lands that have opened/will continue to open at the Parks. The beauty of non-media IP attractions is that they are often timeless in nature and bend with changing interests - that's why attractions like BTMRR, PotC, HM, Space Mountain, Living with the Land, Spaceship Earth, Figment (in theory), Test Track, Soarin', etc. are all still popular with guests, regardless of whether they're interested in a specific movie or TV show. What's going to happen in 25 years when nobody cares about superheroes, just like audiences stopped caring about Westerns or gangster films? (Also, the reason why attractions based on the classic IPs, i.e., in Fantasyland, are still relevant is because those films are timeless stories - many of Disney's current media is not, at all).
The problem here is that Imagineering has a mandate from management to implement more IP into the Parks - I'm sure there are folks at WDI who are extremely clever and creative, who have thought of park-exclusive, original ideas. I guarantee you that the second those ideas are presented, WDI higher-ups/management from TWDC shoot them down OR repurpose them to fit a preexisting IP. And it's not because "it's what people like", it's because Bob Iger is creatively bankrupt and hellbent on proving that the very, very costly acquisitions he made during his tenure were worth it (read his autobiography "The Ride of a Lifetime" and I promise you'll draw the same conclusion). It's done under the guise of "more timeless, more relevant, and more Disney" to shift the hot potato into the hands of the consumer, who Disney has now painted as too stupid to care about any attraction other than ones where the guest points and says "I know that thing from XYZ movie!".
SWGE, Avengers Campus, etc. are neat in concept and pieces of these attractions are impressive in execution, but the motive for shoehorning them into the Parks is nothing more than what I indicated above, and as an advertisement for Disney+. As Chapek said a while back, Disney+ is essentially the Company's gauge for parkgoers' tastes. Now, sure, this might be a sound financial move in the short-term - they are a publicly traded Company, after all, and have a responsiblity to shareholders to turn a healthy profit. Whether that's from merchandise sales, park tickets/LL+, or Disney+ is irrelevant once it all consolidates, it's cash in vs. cash out. However, Disney guests have proven that they are perfectly smart enough to enjoy experiences that are not based on the most recent film by Marvel, Lucasfilm, or Pixar. Like I said above, what's gonna happen when SWGE, Toy Story Land, Avatar, Marvel, etc. are irrelevant to consumers? It's a lot easier to [insert new attraction here] into an area of your park that wasn't purpose-built a specific IP; to me, that's long-term foresight that management lacks. Believe me, I get all the buzzwords, synergy, leveraging properties to sell merchandise, interconnectivity between attractions and media, etc. - I understand that the bean-counters probably determined that the NPV of tearing-out ROA/TSI and building Cars + all the shops meant $X million in future cash flows. That's all well and good. But there's more to making a business decision than just cash flows; Disney is a Company whose reputation is built on decades of goodwill, to which the accountants (of which I am one) can't determine a value.
But what do I know. These are just my thoughts, and all of this could blow up in my face. I'll come back to this in 25 years and take the heat, if I am wrong.