Wow something that happened recently and ended up making a better product.
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Blizzard merged in the first place after a big hiring and company expansion because they were looking to get a great deal more money. Until VERY recently leadership in blizz was still all pre-merger people. Likewise we've seen loads of examples of blizzard employees being great big pieces of shit as well.
Merging with activision was a symptom of what was going on, not the cause. They went the route of MANY major developers when they start getting a lot of money: they only care about making more.