Chill pill. I said somewhere I wasn't an English teacher - I'm not a biology teacher either but DD is just talking common sense. I think 'gene pool' just about covers it.
We can expect to beat the likes of England on the park if we get our best 11 fit. If they have 6 injuries they can pull in another 6 of equal quality - we can't. And there's a fair chance that the 6 will be an inch taller and a few pounds heavier than what we've got.
Crops of decent players only come around periodically. Look at the current Welsh team. Best Wales side in my lifetime I would say.
Now that the world is a considerably smaller place, small nations like ours are only punching our own weight, not above it as we always didbefore. In fact, thanks to people like Levein and Vogts, we are punching below it at the moment.
BTW England have plenty problems of their own at International level, IMO. But our problems have emerged more quickly because of our size.
I'm a Nat too but I don't really think sport is very important (too much like Hitler in 1936). If we were comfortable with ourselves as a nation we would be happy with just the taking part.