The PS5 actually sells better than the PS4 currently, and the lead is getting wider
It's still too early to make any long term predictions at this point. Clearly, the PS5 is more in demand at launch than the PS4 was. The real test will start in September when PS4 weekly sales really started taking off. Can Sony produce enough PS5s to have multiple 300K weeks by then, and nearly 1M units on Black Friday week? Time will tell.
XBox Series X/S should comfortably outsell the One most weeks right up until the holiday season even with current production.
Personally I think both consoles will outsell their predecessors, but the Xbox by a little bit more, if no other reason than it has a lower bar to clear than the PS5 does. And I think both will do better because I think the past year will have a long-term effect on video game demand that will boost this entire generation. Not saying that COVID itself will last years, but that the lockdown periods got more people into video games that will continue to enjoy them even after COVID ends in all parts of the world.