Oh it's easy to explain. Steve Jobs said it best [1]. He talks about innovation at Pepsi being a new bottle. That's what Activision Blizzard is. They have a "monopoly" with their key franchises, most notably CoD and WoW. They just release a new "bottle" every 1-2 years.
Game studios are a bit like a large film studio. They don't like the creative process. It's too unpredictable. They want a formula to produce content that can be predicted, projected and tracked.
Here's another key point: everything you do as a company either adds to or subtracts from your brand value.
For example: Square Enix giving discounted subscriptions and a general mea culpa around the original FF14 release, brand value add. Blizzard adding micro-transactions to classic TBC? That's nothing more than the short-term extraction of brand value into money.
It's a bit like delivering pizza. You're trading long term car depreciation and maintenance for short-term cash.