It has to be true that their intent as of the day of the meeting is to invest $17B over the next 10 years. They have a 10 year plan and I’m sure that number is in there somewhere. Are they contractually required to spend the money? No. The SEC very loosely regulates the content of an earnings call and the auditors will at least take a look at it, but nobody will go back after the fact to see if you follow through. The street will judge you based on your transparency. If a company consistently gives earnings projections or capital spend numbers that are wildly inaccurate they will get called out on it by the sell side analysts on the call who built a model around those projections.
I think the bigger point which is a valid one is that Disney is showing their intent to grow their business and expand. The $17B is probably less critical than the 13K jobs. What is the point of a development agreement? Why would any local government want to give a landowner control over developing a property? The short answer is the development is good for the community. Disney adding 13K jobs is a big win for the local economy.