Most PE companies purchase a firm with lots of cash and/or good cash flow, drain the cash and replace it with debt, keep the investment for a few years and sell off the asset. From what I've read Highlander Partners purchased McIntosh, but was very much "hands off" and probably made a good return on their investment because of that. I suspect that Bose won't cheapen up this brand, too much to lose if the quality slips and it's not respected as the sort of high-quality product it currently is.
McIntosh purchased by Bose...NOT an April Fool's joke.
Unfortunately, the world is officially in decline.