Not exactly. The key here are the words "controlling interest."
Now that a major development/luxury hotel company has a controlling interest in the ski resort expect things to change, and quickly.
There will be more development, particularly high-end real estate. The mountain will become more crowded and there will be a much larger bed-base of ski in/ski out short-term rental properties.
That doesn't mean Mammoth will start to suck. But over the next ten years the charactor of the resort will become markedly different. Sadly, lift ticket prices as well as season pass prices will probably increase, too. And there will a cookie-cutter village al la Interwest, the developers/owners of places like Whistler and Copper Mountain.
If you don't like that kind of stuff, go to Mammoth this year, because next year will be the beginning of the end. . .