They've been squeezing more money per person continuously for a while now. This is how they have higher revenue than ever before. And by capping the capacity at parks, they're staffing only as much as they need, keeping costs down.
They don't want "volume, volume, volume!" That just makes the parks supper-packed and lowers GSAT and hurts the brand. A packed park means people can't ride rides, can't pay premium at TSRs, and can't fit into a store to buy merch, not that they'd feel the love to do so with the unpleasant experience of an overcrowded park.
The "brand" makes Disney a premium experience (even if some other theme park is offering better service and a better experience [and no, that is *not* Uni, from personal experience]). And people are paying more. And they pay even more when there's less people crowding them. That leads to bigger net profits.
Yes, the 50th is a bust. But it's not stopping WDW from hitting full parks goals.