Ah, yes, because these companies didn't make enough money off of their golden legendary deluxe season pass editions of the game. Individual DLC purchases, sometimes subscription services. Oh, and the massive amounts of merchandise that gets sold across a stupid amount of things like shirts to logos on a coffee mug. What about the sponsorships and partnerships with food companies? Ah, those are just rookie numbers.
I hope you realize that, if microtransactions weren't pulling through metric stufftons of money, they wouldn't add them, and they wouldn't try shoving it in your face as much as they could. There's a reason that developers add special editions of games, and it's because there's a market of people who have money and don't give two stuffs. They spend the money even if it's not worth it. Microtransactions are the same concept.
Also, no. Developers are paid the exact same amount if the game suddenly blows up or if the game doesn't do hot, give or take just a tiny bit of leeway there. The ones profiting off of a boost in sales are the higher ups.
I'm open for McJob to come by and refute everything I've said though. I'm only basing it off of speculation and personal experience.