They're a company, not a family member. They don't owe anyone any loyalty and they're quite within their rights to buy up whatever other companies they want to make whatever products they feel like. That's business, stop having so much emotional attachment to it. The better question is why hasn't anyone else stepped up? Can't blame everything on Microsoft, they've left plenty of opportunities for competitors with regards to PC gaming and the industry has fumbled them continually.
Playing: Xenoblade Chronicles DE, Ys IX, God of War
Watching: Lupin, You me and the Apocalypse, Days of Thunder