For the very examples you listed you have actually made it clear why Walt Disney World is (or at least, was) unique in this regard.
Your examples of how you have no problem with booking in advance: the cruise - well, a cruise is set with a specific number of passengers who can be on the cruise, be it 500 or 2000 passengers. So, yes you need to book in advance to be one of those passengers if you want to take that cruise. New York show tickets - likewise, the theatre can accommodate X number of attendees per show so once again, you need to book in advance to guarantee yourself a seat at the showing. Red Sox tickets for a game - check! Hawaii trip - transportation and a tour - also limited by seating or attendee count - check! Dinners on special occasions - there are only so many seats in a restaurant so booking is a must as you noted. But these things you listed are all individualized "events" that by necessity needs to be limited per event - no flexibility to really be found.
Disney World, on the other hand, has always (or used to be) advertised to potential visitors as a place where you can be flexible because there are 4 parks you can visit and "hop". So on a given day you used to be able to have the flexibility to run/hop around at will to enjoy the parks as you might see fit. You were able to start in MK and maybe decide it was getting too crowded so you hopped on that monorail and headed to Epcot whenever you wanted. Your kid woke up that morning and decided he wanted to eat at the Japanese hibachi place for lunch so instead of going to Animal Kingdom in the morning the family decides to go to Epcot instead. These things you were able to do with great flexibility before. So if someone is bemoaning the loss of the flexibility that was available in the past at Disney World it is understandable. At least to those of us who understand the difference between instant park hopping at Disney World as was allowed in the past versus the sort of "hard ticket" examples you listed which by their very nature have always allowed little to no flexibility.