Wales due to population size is overachieving already by qualifying to a WC from Europe.
What nations like Scotland and Wales did in the past, producing top players in 70s,80s, and 90s, was already a massive overachievement considering their population size, which was even smaller back then.
That context should always be mentioned, which is why I always praise Uruguay,Croatia, Serbia, etc cause they produce top players despite the very small population.
For example, brazilian football is as dominant as you would expect them to be, considering the massive amount of money they invest in football (only 3-4 countries in Europe invest more than them) and their massive population size, the surprise would be if they were less dominant.