My M1 Max was released in November 2021, I ordered almost on day one and it was delivered in February 2022.
I'd rather have them launching and releasing in March than messing us about with the dates. If it means I have to wait Q1 2027 to upgrade then so be in. I can't find anything wrong with mine besides the weight.
Makes sense, the iPad Pros will easily outsell the MacBook Pros, so, make sure those orders are fulfilled first, then the less popular systems get them later.
Might as well wait for the tariffs to end. My M1 MacBook Pro, M2 iPad Pro, and M4 Pro Mini will keep me humming for years. (Not to mention my Home Assistant Yellow running on a Raspberry Pi 4.)
At the very least, I would expect it at least by January. Will be a minor update with only a chip change. If it launches only after January then I think there will be no M6 version in 2026 and 2027 might see the launch of iPad Pro as the first device with M6.