I haven't encountered this, but I've also only used the Apple Silicon devices. This might explain why there are so few ports, though: Thunderbolt is basically PCIe and has AFAIK direct lanes to the CPU; more full-featured ports = more PCIe lanes = much more complexity/expense.
The difference is in the desktop systems. That's where there are USB-C ports without Thunderbolt (e.g. Mac Mini).
Damn, you're right. I have an M1 Mac Mini and both ports are Thunderbolt. I recall, and Wikipedia corroborates, that the M2 Mac Mini could come with either two or four ports, but all were Thunderbolt. Now though, the M4 ones, besides getting an awful facelift, also seem to have sacrificed one Thunderbolt port (and both USB-A ports?!) to "gain" two non-Thunderbolt USB-C ports. What a terrible trade IMO.