If you took the ambitious leaks at face value then I could see why it would be a surprise. Nothing has changed with chiplet Zen 3 except for the addition of cache, and this refresh doesn't get that much time on the market. Bottom line is, 2022 has always belonged to AM5 if AMD intends to stay on track.
Rocket Lake was also in the same boat timeline-wise, but OEM's needed new stuff, so they had to release a [relatively] full i5/i7/i9 lineup as a stopgap. But otherwise, same deal.
The -200MHz boost clock deficit feels like AMD is trying to present the 5800X3D only as a technology demonstrator only.
My concern is more over what the -200MHz means. Is the L3 that power-hungry that it digs into the CCD power? Are they trying to limit the 5800X's performance on purpose (not likely, Zen 3 doesn't scale much on freq in games)? Or does the 3D cache + thermal spacer over the core area cause a thermals problem over the 5800X's already poor thermals (so far L3 seems to run relatively cool on my 5900X since HWInfo added sensors)? That might be really telling about how AM5 behaves thermally.