I think one other factor that we sometimes forget, is perceived value can be a very individual thing. One person could see value in having three M.2 slots, where as another might think it is a waste and that you could just put a PCI-E riser card in that will take 2 or 4 M.2 drives if you need more slots in future. The same can be said for what you are suggesting, buying a 3800X over a 3700X, how one person values the extra £70 spent vs. another thinking it is a waste of money, especially when they are the same core/thread count, and it is inevitably going to be swapped out.
It was much easier in the earlier days of PC, back when you'd have bought a top of the range 386 DX33, only to have it obliterated by a new CPU after 6-9 months and knowing it was coming but still buying it anyhow.