They would be idiots. That argument never really held much weight but, it especially holds none now. If a person can't find a game to play on either console then I kind of feel bad for them.
Regarding exclusivity, I agree that it's one thing to fund a game and have it exclusive (Sunset Overdrive) and another to just bribe someone to keep it on your platform. The first scenario helps a game get made; the second one screws over gamers.
I've never been a fan of exclusive content unless development was funded. This counts timed exclusive stuff as well, which I especially loathe. It seems like a cheap way to make people think they need your console and, in reality, anyone with a brain can see that all it does is screw over half of the gaming population for a couple of weeks.
Based on Titanfall, PvZ:GW and Tomb Raider, it's starting to seem like the $1 billion Microsoft was touting to invest on exclusives at E3 2013 is mostly going to be spent on locking away 3rd party titles. Games, that would have been released simultaneously on multiple platforms otherwise. When it would be more wise in the long term, and less annoying for the gaming community, if they put that money to bolster their 1st party studios, and create new IPs.
I guess if either say exclusive, we just have to assume that the game is also coming to PC, mobile, Nintendo DS, and the opposing console (but for that one, six months later).
On a similar topic about the term "exclusive", what about the term "free to play"?
At this past E3, Sony had a segment about their lineup of F2P titles. During the trailer however, there was a disclaimer on the bottom that said "Certain Features Available for a Fee". Doesn't that disqualify the F2P term? At that point, wouldn't you just call it a demo?