As several here have said, this is lineup rationalization. It means we get a couple of machines that don't really get an upgrade this year, but it means there are a much wider range of choices (oddly NOT including an 8 performance core machine, which was the sweet spot for a couple of years - that really IS odd).
Counting performance cores, the M1 and M2 lineups went:4,6,8,8,8,16, with the 16 being desktop only. The bottom of that lineup is great (nobody was clambering for a 5-core or a 7-core). Why three different 8-cores, though? With two names?And that's a big gap between 8 and 16 cores.
The new lineup goes:4,5,6,10,12 (20,24 assuming the Ultra is what we think). The biggest gap in there is that there isn't an 8-core. The gap between 12 and 20 cores is both smaller (percentage-wise) and farther "out" - the 12 core Max is a very high performance chip, satisfying more needs without going to the Ultra.
They pushed performance out quite a bit by creating a higher-end option than they'd ever had before (12-core Max - of course it's more expensive, it's only the fastest laptop in the world by a significant margin). The 10-core Max takes over the price and performance space of the higher end 8-core Max with a nice upgrade.
There's definitely a chip missing (and one has been added right above the base M3). The 5-core Pro doesn't really fit a space where anything has been before - it's more than a base chip, but less than the previous smallest Pro. The 6-core Pro is a nice upgrade to the previous 6-core Pro, but not a replacement for the 8-core Pro or the lower-end Max.
They need one more chip, another cut-down of the Max (or call it . 8 Performance cores. If they offer an Ultra version of it as well, their lineup would go:4,5,6,8,10,12(16,20,24). That's a REALLY nice lineup, eliminating the gap between 6 and 10 cores AND making the gap between the top Max and the Ultra much smaller.
There's talk of both an Extreme (double Ultra) and, on the far opposite end, a very low-end Mac for the education market (might it use an A-series chip with two or three performance cores?