I don't need Xbox personally, but you are wrong on X1 or Series burning money from MS. They may not have high profits (MS doesn't show the numbers), but the HW itself hardly is losing more than 1 or 2 games worth of profit, so considering the 10+ average it console sells and the subscriptions the HW itself is advantageous to MS.
Regarding needing MS to keep Sony in check I don't believe in it, PS2 dominated the market with easyness and still had price, quantity and quality while PS4 had a much stronger competitor in X1 and didn't cut prices besides once and in PS5 situation is similar regarding sales and besides the price increases due to inflation/exchange ratio there is no interest from either MS or Sony to cut prices at the moment.
duduspace11 "Well, since we are estimating costs, Pokemon Red/Blue did cost Nintendo about $50m to make back in 1996"
http://gamrconnect.vgchartz.com/post.php?id=8808363
Mr Puggsly: "Hehe, I said good profit. You said big profit. Frankly, not losing money is what I meant by good. Don't get hung up on semantics"
http://gamrconnect.vgchartz.com/post.php?id=9008994
Azzanation: "PS5 wouldn't sold out at launch without scalpers."
Essay Pro