Yeah, it seems like a time to wait unless you are either in urgent need of a new Mac or can afford living on the cutting edge. The M1, like the A series used in iPhones, is a “system on a chip”. That’s a large part of the reason it gets such amazing performance. But it also means that the available resources are limited forever to what Apple put into that particular chip. There are some aspects of the M1 that are less than heavy-duty users would want. For example, the total memory (CPU and graphics use the same memory) maxes out at 16GB. Not bad, but not as much as demanding users need. It won’t affect single-thread SketchUp, but the number of cores is also small and fixed. The number of external ports on the M1 is too small for a pro-level computer. So, expect to see Apple roll out more advanced versions over the coming years.
And yes, it will take years - but probably fewer than you might think.
So far as I know, Apple themselves don’t put old models on sale. But they do allow resellers such as B&H to sell their old stock at reduced prices.