It depends on who the investors are and what they want. Yes, there are some awful privately owned companies. But at least when privately owned, it feels like there is a higher chance that the people involved actually care about the business the company actually performs.
As for how Activision would behave if privately owned, we don’t really know. Activision was founded in 1979, and ten years later it had already lost all of its founding members and much of its talent.
In 1991, Bobby Kotick swooped in to buy the debt-riddled Mediagenic (a prior management change had led to a name change in 1988), and Kotick was only doing so for the money. Kotick saw video games as a money tree, and that’s pretty much the idea that he’d sold to investors. He’d promised inventors that he’d grow the company without going below the break-even point, handed out stock to offset debts, fired 95% of the employees, raised $40 million by going public on NASDAQ, and by various other tactics met his goals over those first four years. Then he switched into dev studio acquisition mode to make more money.
Heck, the Vivendi merger was driven by Kotick wanting in on the perceived MMO money tree, with its subscriptions and microtransactions. The deal was apparently cemented when Kotick learned that Blizzard was expanding into China’s market (which carried a promise of an even greater money tree.)