2TB HDD 100$ for those >100GB games
4 years PSN 240$
900$ just to get you in the door
You could buy more than 15 Stadia games for that. This may not appeal to core gamers but the more casual crowd will definitely take a look at it.
We don't know the price of the PS5 yet.
You don't need a 2TB HDD if you buy your games physical. And you should, because physical games are almost always cheaper than digital on the PSN store.
You don't need 4 years of round the clock PSN coverage. Only half of all PS owners are subbed to PS+, and a lot of those people are subbed to it for free games, not for online.
You'd only be able to buy those 15 Stadia games if you went with the free version of stadia at 1080p. But next gen that will be as antiquated as playing your games at 720p.