Yet just three short years ago people were saying that very thing about AMD having any impact at all on the market place, now look where we are. The 10900K and 10700K would not exist had it not been for AMD, and every generation they have become faster in every single way, and every usecase.
As I said at the start of the thread, buy a 10700K, Z490, 32GB DDR4 RAM and you are done, don't worry about losing out on performance in the long term, or look at the longevity of the system just concentrate on what matters to you now! It's not going to get any slower once you've bought it, just other things will come out that are faster, cheaper etc.