This isn't the primary console buying to remain in power. This is the current third place platform buying to be a competitive force.
Considering Nintendo just does Nintendo things and I doubt either company really sees them as a competitor (which isn't a bad thing to be clear, but they clearly have different ideas of gaming).
We basically only have Sony here who has a long history of anti consumer tactics that in my opinion do a lot of harm on the gaming space. We are starting to see the Cocky "we can't do anything wrong" attitude from Sony again this generation that we saw when they first announced the PS3. That is bad for gamers and the industry. Just look at the complete opposite approach that Sony took with the PS4. Sure they still made some of their questionable decisions, especially later in the generation.
The fact is we need a strong competitor to Sony and Microsoft has made a lot of strides to get there, but this acquisition will put them right up next to Sony.
Now yes, Microsoft has a history as well. Particularly during the 360 generation, we can't ignore that. But we also can't ignore that Phil Spensor was not in charge at that time.
We also can't ignore that as gamers. Activision Blizzard has been in a bad state for a while now. Sure they may still be raking in money, but their games have continued to stumble over the last few years.
That is before you get into all the harassment issues that a drastic change is necessary and honestly I don't know what other company I would actually want to buy them. Sure not Sony, EA, and outside of those... who could realistically afford too.
For the record: I am saying this as someone with all 3 consoles and a gaming PC. But my playstation is my least used console because I despise many of the business practices that Sony gets into. I don't want to reward those behaviors.