It says minimum of 8 billion under the economic development terms in Exhibit C:
"Disney agrees to make at least an initial capital investment of $8billion dollars within the first ten (10) years of the term of the Agreement, consisting of capital investment in existing infrastructure, new construction and technology investment."
They may well end up not doing all 17 in the first 10 but that is a pretty typical safety measure to guard against unforeseeable economic issues (think 9/11, housing crash or Covid) where you need to drastically reduce spending.
Personally I don't think they do all of it in 10 years as I expect a new CEO to come in long before many of the projects that money would go towards have started, halt everything to evaluate the potential projects, can a number of them and restart the whole design process pushing things back years.
That's been the caveat that so many have missed all along - Things change.
And so many were saying, "nope, Bob said it, they filed papers with the SEC, they are LOCKED IN on that $17 billion in the next 10 years, baby, they're going to build tons of new things!!!!!!!!1!!!1!". No common sense, no peeling back a layer on the onion, just keep their pixie dust drip going strong and everything is fine.