I think you should visit the parks more often. Clearly, you've missed what they've built in the past 20 years.
Pandora, Galaxy's Edge, Toy Story Land, Mickey & Minnie's Runaway Railway, Cars Land, Avengers Campus, Fantasyland Redo at Magic Kingdom, Seven Dwarfs Mine Train, Soarin', Disney's California Adventure Park, Little Mermaid Dark Ride, the 20-years of tinkering and changes at Disney's California Adventure Park, Guardians of the Galaxy Mission Breakout, Frozen Ever After, and Disney Springs. Let's not forget the upcoming Guardians Coaster at EPCOT, TRON at Magic Kingdom, and the Rat Ride in France.
They're creating plenty of new stuff. You're just not giving them credit because you don't like what they're building.