It's a false economy buying a Windows laptop for most people, because you absolutely do need to upgrade sooner rather than later.

I think you missed my point.

You want to keep laptops for ages regardless of what OS it was it runs (really not sure how that would have any bearing on spec fall off), but the MacBook M1 is only competitive now, but it won't be competitive in 4 to 5 years. The chip is good for its power consumption but it isn't a particularly high performance chip in terms of raw numbers. But the laptop costs as if it is a high performance chip.

There's no such thing as a Windows laptop you just buy a laptop and that's the specs you get so not quite sure what you're comparing the MacBook too.