That's true, they could eventually price themselves out of the market.
But, every year---after each ticket increase, each
DDP price increase/component reduction, each menu change, each resort price increase or refinement of seasons to raise prices---people suggest that, finally, this will be the straw that breaks the camel's back. It hasn't happened yet.
So far, people keep going to the parks, eating in the restaurants, and staying in the resorts. So, Disney hasn't gotten there yet. This is the second year of "seasonal" restaurant pricing, and those character meals still book up. I was there last summer, and there was no shortage of people wanting to visit the buffet locations. You may not be spending as much, but someone is. Total domestic guest spending was up in
the most recent quarterly report.
Edited to add: don't get me wrong, I don't like it any more than anyone else. But, I accept that it's inevitable. We only did one buffet meal last summer (lunch at CP), and now that my youngest is a Disney Adult, it gets even harder to fathom. But, we did eat at some of the a la carte places instead, and had some really nice meals.