Too many wild conjectures, made up numbers, and even strawmen gamers. The first parties aren't losing a billion per year every year (which is what would be needed to pay for a drop that is significant), that would be crazy. According to Yoshida the sum is profitable and it's his objective to stay like that (two or three hits paying for all the others) so that billion loss figure doesn't make sense.
I'm not saying they are incurring a huge loss, what I'm arguing is that is it worth still doing that, having a bunch of losers funded by a handful of winners even if that is currently slightly profitable. Is that worth it compared to the alternatives that can be done with that same sum of money, one of which I suggested is dropping the price of entry to get more people into the fold and hence spending more on Sony services. Another could be offering better bundles or pack in games. Or maybe spend that money buying exclusivity time windows on key games or exclusive dlc. There's lots of other options rather than just "exclusives".
I don't understand why you group together the gamers who praise them and the gamers who didn't buy them. Seeing first parties purely as direct money makers is incorrect as it's helping the platform as a whole, the platform itself is the most important reason to make those games. Each gamer will have his/her own rational reason to buy a console or a game. The less the sum of this group overlap in tastes, the more advantageous it is to have a genre variety. The third parties will NOT do that and will only make the same popular genres over and over (the games that defined the expression "hardcore gamer" on PC, or "PC master race", or whatever it's called today). The platform holders have a different goal and they profit from having variety regardless of each individual game's sales figure. It's not like the entire gaming community is some collective moving as a single mind. Each genre, heck even each individual game, will appeal to different demographics. The less the overlap, the higher the sum of console sales. Right now I tihnk Sony is meshing very across third party offerings.
There are many things that can help the platform as a whole, it doesn't have to be just about exclusives. There's other ways, possibly better ways to entice people to the platform. That's what I'm getting at. Given finite resources (cash) it seems to me they could be managing that better than they are right now.
So I think genre variety is the correct decision and it's the most profitable use of first parties for the platform. And about the risk, who knows which of the first party studios will become the next Naughty Dog, or the next That Game Company, or the next Media Molecule, etc... It gives the platform an identity, and it helps the prestige of the brand.
I think they would be better off identifying key companies early in their lifesspan and partnering with them for short term benefit, then moving onto the next. Aside from a key one or two companies, I don't think they need to be fueling all these studios themselves, I don't think that is a winning solution anymore.