> why wouldn't they just sell it?
Serious question, is there any kind of entities that can be owned, but not "dismantled", if you don't want it you need to try to sell or make it independant.
Would there be any chance to make it a thing when a company is bought?
I get the impression European companies are like this. In general if a company can't be reorganized/dismantled that makes it worth so little (or negative) that no one will acquire it.
You can put various kinds of "poison pill" in the shareholder rights agreements which are binding contracts on both the company and its shareholders in response to events.
You can also make all sort of post acquisition agreements.
These usually take the form of making stock available at steep discounts in response to actions e.g. in the event of a 20% layoff any employee from the time of acquisition can purchase stock at $0.10 a share, any one laid off will get a million dollars severance, if acquirer shuts down the studio the original founders have the right to re-acquire all IP and trademarks for $1 -- those sorts of things.
This isn't a specific kind of entity, any business entity can have Shareholder Rights Agreements. It's a bit of a game to get the terms right so everything is in good faith and agreeable.
It's fairly common for a studio to buy its independence and keep the team intact. You do need fresh money to make it worthwhile and give the new studio runway.
There's also the case where new teams can self organize to form new studios in the aftermath. That's also a factor on whether it makes sense to pay for the previous name or game license, or simply start over.