I don't want to speculate about why there aren't enough dev kits.
If any system has a power advantage this time around, I don't think it will be nearly as big a deal as it was with PS4 and XBO.
And I don't think Scarlett or PS5 will have similar issues.
Not sure if the world changed by now, but on gen 7 there were plenty of comparison of PS3 and X360 games even when the difference was minute.
duduspace11 "Well, since we are estimating costs, Pokemon Red/Blue did cost Nintendo about $50m to make back in 1996"
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"