Zen5 was released less than 2 weeks ago, so not a terrible delay.
If you already have Zen3, then yeah, probably not worth it. I like to wait 4-6 years so the upgrade feels more substantial. Every 2 years hasn't been necessary for at least a decade.
It's a terrible delay w.r.t. reviews, because all the reviews were done without these improvements. First impressions are very hard to fix, and Zen5 is already widely regarded as a flop, at least for desktop/gaming usage.
If you already have Zen3, then yeah, probably not worth it. I like to wait 4-6 years so the upgrade feels more substantial. Every 2 years hasn't been necessary for at least a decade.