Eh... I don't think so really.
Depends on their objective. A PS5 sale is more valuable to them than a PS4 sale, because the PS5 owner will probably generate more revenue for them in the long run. Selling more systems isn't necessarily their goal. And even at 200/250 I don't see the PS4 being a very attractive proposition because of the 300 dollar XBox Series S and Swtich.
The PS2 had a lot of success post PS3 but that was a different market, and Sony was launching the PS3 at a very high price to the point where a cheap PS2 wasn't going to influence it. I can see Sony just letting hardware sales drop quickly.