It's the truth. They can't just infinitely expand the park. They can't keep attractions and areas around as museum pieces, and hope that the audience is willing to pay for continually running these rides and attractions they don't want. They can't just keep assuming people will be willing to walk miles past the main entrance to get to the newest, best rides.
They are taking an informed approach. They tried to do an update of the island/river at Disneyland... multiple times. They know exactly what their money bought them in utilization and guest satisfaction. They decided that spending the money on fixing the river and island at WDW wasn't worth the money, and that a larger scale project and new attractions would be a better use of their money. They're absolutely right.
Everything they do should be about money. You can, if you want, choose not to look at it that way. They routinely do things that cost them money but emphasize guest satisfaction and brand loyalty. They often go out of their way to preserve and celebrate their history. There are just limits to that. You can't run a theme park full of museum pieces unless you can keep people paying the high entry prices. And high entry prices are justified by new expansions and attractions.
Far better to have a park that changes and adapts than none at all.
When the river was built, Big Thunder wasn't there. Tiana's wasn't there. Villain's Land wasn't being planned. Today's Imagineers have the knowledge of how the river exists today and what they want to do in the future, so of course any new project is going to be better integrated than what has organically sprung up over 50+ years.