Thor has not been entirely "hands off." Not too long ago they merged their FourWinds and Damon into Thor Motorcoach. This was probably for the good, since they eliminated some internal competition with alike product, and introduced new lines like their A and C RUV products.
Thor Motorcoach is still making multiple "brands" of most model lines, like the FourWinds/Citation/Chateau branding FourWinds used to do, and new pairs like Compass/Gemini and Axis/Vegas, but no longer have Damon Daybreaks aimed at the same market as FourWinds Hurricanes.
But generally, they've let Keystone, Dutchmen, Airstream, Crossroads, Cruiser, Heartland, LivinLite, DRV operate on their own. I'm less sure about the ongoing independence of K-Z, and Carriage was one of the companies that essentially disappeared, with the brand names going over Crossroads, with loss of the construction methods that had made Carriage special over the years.
Better chance of survival for a company to be pulled into the Thor group than to be bought by Forest River, which tends more to centralize management and merge production facilities.
Also unlikely that it is a cash buyout, more likely the sellers will become partial owners of Thor. I could see this coming when Jayco had trouble getting Entegra going. A family-held business can have difficulty raising capital for business expansion, and most of the failures of these small, closely-held RV manufacturers have been the result of creditors calling in loans as soon as business gets slow.