I saw a post on reddit earlier today of a man on the speeder-bike at DHS from 20 years ago paired with a photo of the same man now with his baby together on the speeder bike. I feel like that's really all you need to understand why it's important to preserve the parks, even if that particular speeder bike isn't anything historical or special. The way Disneyland is able to transcend generations is one of its greatest strengths (beyond just being artistic masterpieces).
Amazing too, since DHS is hardly Disney's greatest theme park. Disney needs to eventually realize that while drastically changing Fantasmic, the Tower, Star Tours, etc. away from their original creative intent into entirely "new" entities might boost attendance short term, but long term, the parks could suffer greatly if the emotional link guests have to these attractions is severed.
The rate of change that Disney's been tweaking DCA has basically invalidated any fond memories people have had from the 2000's. They've basically alienated the ToT and Soarin' fans, Grizzly River Run is the least changed attraction in that park. They desperately need to start putting attractions in there that are good enough to become timeless and classic.
Perhaps I'm a bit more cynical that the average park guest, but I have zero desire to ever return to DCA- I couldn't care less about the new Soarin', Guardians of the Galaxy, The Incredicoaster. And if I'm gonna get wet on a Disney ride, it needs singing geese and talking rabbits. I used to have a "spend 3 hours in DCA to hit the good stuff, then hop on over to Disneyland" mentality, but now I avoid the park like the plague.
It was amazing visiting Disneyland with my extended family (including my grandparents) a few months ago, and hearing their stories about visiting from the 60s, 70s, and 80s.
"I remember when this opened" while waiting for the Tiki Room.
"I remember when the line for Star Tours went all the way out here" while standing in the hub by the Plaza Inn.
"I remember visiting the park opening year for this" while waiting for Fantasmic.
Attractions like the Haunted Mansion and Pirates, while changed, still (mostly) resemble what they were on opening day.
Space Mountain is more a 2005 attraction that it is a 1977 one, but even with the addition of music, the revamp of the effects, and the entrance/queue changes, it's still very much Space Mountain. That's how you update an attraction for future generations.
Big Thunder is another excellent example, and while I wish the bobsled design was a bit better, and that the new Harold had the same art design as the original (just with the updated technology), it's still very much "the Matterhorn". The Fantasyland Dark Ride enhancements were also delightful.
