I see your point, and I understand what you mean, but that is where the subjectivity of this thread and this mindset as a whole comes into play. I look at what has been added since 1998 and see it as far outstripping what has been removed. For example, EMH and the dining plan were added after 1998! The fact that they have continued to evolve does not belie or negate the fact that they were additions post-1998.
Expedition Everest, Toy Story Midway Mania, Osborne Family Lights, Soarin', Test Track, Mission: Space, the Fantasy Land Expansion, multiple resorts, Magical Express, etc. have all happened since 1998, as well as many other additions, so it hasn't been 14 years of retrograde devolution, in my opinion.
The additional challenge is that as things mature, they will always evolve more slowly, and so arguments that only look at the "debit side" instead of both sides, in my opinion, do an injustice to the conversation. For example, I understand that WDW added a park about every 10 years, but that is an unsustainable model, so they have been adding parks around the world and focusing on other parks since that time. They do not want a fifth park in Orlando right now because there is no business purpose in adding one. Does that mean they are "cutting" or simply using good business sense? What about after five gates; would we need a 6th?
Can you imagine
ticket prices if they invested $25,000,000,000+ in a new park?