PS5 got off to an early lead. Clearly, there was a lot of demand for it from the most hardcore gamers. However, it has been losing ground to the PS4 for the past year, and it's going to continue losing ground for the rest of its lifetime. Shortages are really only the least of PS5's problems. It has the much bigger issue in that it's really only going to be popular in Europe this generation. PS5 will be a distant third place in the US, and it's obvious that there is not much demand for PS5 software in Japan and RoW.
I mostly agree with you.
Only I am not sure if it will finish worse than the PS3 (although I am not ruling it out as a posibility) but could also see it reaching 90 or 100M. We will see.
Certainly this time Playstation has bigger competition in the face of both Microsoft and Nintendo and this will impact the sales decently.