PS4 Pro production is likely going to stop within the next few months, so it won't be a problem.
The point of Sony's crossgen games isn't to move more PS4 hardware, it's to make money with software sales alone. The PS5 will be sold at a considerable loss based on Sony's muted profit forecast in their gaming division for the current fiscal year. Because of that, you shouldn't expect any permanent PS4 price cut anymore, because it's probable that the PS4's remaining job is nothing more than mitigating the incoming PS5 losses.
Sony's forecast of 9m for the PS4 this fiscal year leaves enough room for another round of temporary Black Friday/holiday deals. That's about it, although one has to wonder if Sony will really want to give the PS4 another such push with the PS5 launching at the same time.