Sooner than you think, but beyond that, not sure.
What I know: imagineering is really busy at the moment. There is a desire to get projects moving ASAP.
Things I suspect: Disney spent a lot of money expanding Marvel, Star Wars, streaming etc, and pumping out as much content as possible, now they’re seeing what works and what doesn’t, and are cutting the fat. Now they’re shifting strategies to throw a lot of money on theme parks.
Currently, the only WDW investments are a DVC tower, a retheme, fireworks, and a nearly finished Epcot hub. Disneyland has nothing outside of a simple retheme of pacific wharf once TT opens this month.
Hong Kong and Shanghai are nearing completion on Frozen and Zootopia respectively.
They’re not about to cut investment funding to the parks, they may even expand it.
Back to what I know. The people I know in Imagineering are incredibly busy designing the projects that will begin coming to fruition in the near term to fit their desired investments. I said it in the Beyond Big Thunder thread, but what I know is they’re working on a lot. Whether it’s a lot of different things, one massive thing, I’m not entirely sure, I have general ideas and suspicions, but once again, I’m not entirely sure.
I am entirely sure, that unless they make a sudden 180° turn, a lot is coming and sooner than you’ll guess.