At this point, I'd agree with you, but market changes can really impact sales. The N64 sold around 15.2 million units by March 1998, which was the first year to year and a half on the market (due to a skewed launch) making it Nintendo's most successful launch to that date, yet falling into a distant last place by the end of its generation. I wouldn't expect PS5 momentum to collapse in the way the N64 did, but I also wouldn't expect sales to be proportional to the PS4. Scarcity can also drive people to purchase a product earlier than they normally would - Nintendo's often accused of manufacturing scarcity to improve demand.
I do expect PS5 momentum to collapse very similarly to the way the N64 did, especially outside of Europe. In Europe, of course, the PS5 will continue to do fine for years. However in the US it will probably peak next year. Once Americans see that Microsoft is really trying again, and Gamepass is a pretty good deal if you like those kinds of games, then Americans will head for Gamepass/XBox. In Japan and RoW, I expect PS5 to peak this year. It won't be such a desirable item to scalp next year out of Japan, since scalpers will have the Switch OLED model instead.