I think the underlying premise is faulty. Those experiences weren't similar any more than two separate roller coasters are similar. They were completely different rides. Again, it's of course subjective, but I think the variety in EPCOT's pavilions was better than any current theme park.
I would agree that just because different rides have similar mechanisms that it does not make them the same or similar. Haunted Mansion and Little Mermaid are the same ride type but completely different experiences which no one would mistake for one another. Same with POTC versus IASW, etc.
But the "problem" with classic Epcot IMHO is not that they used the same ride type or style, but rather that the
experiences were all very similar in execution. Slow moving ride, learn about history, hinting about the possible future in that field. All the rides were excellent, but they all had the same vibe* that could feel repetitive. It didn't help that they were also relatively long rides, so to some that worked against them if someone felt it was the same stuff rehashed in a different package.
Now, mind you,
I liked classic Epcot. But I also can understand how it wasn't everyone's cup of tea and how there were also many who found it boring. And if I'm being honest, I think that works against the general premise of Disney parks where there is "something for everyone in the whole family". I'm not saying there isn't a place for those rides and I am saddened by many that we lost but I do firmly believe that Epcot needed more variety so that the classic Epcot dark rides would stand out and be a contrast rather than "oh this again". The should have done a better job with adding such variety though instead of removing/replacing stuff (e.g. no reason not to add a Mt. Fuji Coaster to Japan).
*I'd suggest that Imagination and (later) Body Wars were the ones that managed to break free and distinguish themselves.
I'm also not sure I agree that the complaint about Universal is that they're too similar as opposed to them being not very good. Although I personally hate Forbidden Journey, if they had two other similar rides themed to a different IP that were as highly regarded as Forbidden Journey, I don't think many people would complain about them all using a Kuka arm.
On the other hand, people have complained about building a bunch of trackless rides, so maybe you're right. I just personally don't understand the complaint because the ride system makes very little difference to me. It's what you're actually seeing in the ride that matters.
I think the argument about Uni
is very much that the rides are too similar. My kids joke about how "oh we're putting on 3D glasses again". I think Uni rides are generally very well done, but it is tough not to get some sense of having just done the same thing. Admittedly, it might be exacerbated for my family because we always stay on property and get Express Pass so we rapid fire hit rides a lot.
The irony is that Uni
does use different ride systems but many still still to hit you with the same "type" of experience - whether it's the 4D films, EMV, Kuka, etc. You are in the world of a film, "something goes wrong", you move around as you are in danger, there's some fire/water/3D effects, you escape. Yeah! To be fair to Uni, they know this and are branching out, but I think many of what people describe as "screen fatigue" is repetitiveness of the same type of experience there.
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