I think that basically admits that the number of teams from each country that has made it is a far more flawed measure than the number of appearances by each country. Especially considering one of the teams in the English counting is Nottingham Forest, who were crap for a long while, won two European Championships, and went back to being crap (generally speaking, of course) - like the Leicester of European football ;).
Forest are a strange team to pick as an example. At the time they were a great team. Strong in the league and excellent in Europe. Clough and Taylor didn’t get their reputations by accident.
A lot of different English clubs doing well in Europe is a decent enough metric for us to say the league has strength in depth. A lot of individual appearances for a couple of top teams suggests the Spanish league has their brilliance concentrated in a more limited way.
Are the top Spanish sides better than the top english sides? I think so. Is the English league stronger overall than the spanish top division? I think so. I don’t reckon that’s too much of a controversial opinion.
I believe they had what, 5 great years and really didn’t do much of anything with the other 140+ years of their history (a few great seasons here and there in the 1960s and one in 1995, but nothing sustained). It’s probably a really good choice to pick ;).
I don’t actually think there is a lot of evidence for the second statement. Seeing, for example, how successful teams like Sevilla have been in the UEFA League, I think I’d say that the Spanish top division is probably stronger overall than the English league.
Anyways, the point is that we can tell who is better at the top of the table, because they play each other (in Champions League) or in the ~3-6 places of the table (UEFA League), but we have no idea how to tell who is better in the mid to lower tiers of the table because they don’t actually face off against each other. So it’s really all speculation at that point.
Though, at the top, if Man City was to actually purchase Leo Messi (as as seemingly been rumored for ages now) and Chelsea was to purchase, say, Christiano Ronaldo or Gareth Bale in response - then you would end up seeing a similar Barca-RM distance to the rest of the league. That wouldn’t make the rest of the teams in the league worse, however. It would just mean that Man City and Chelsea were better (and their results in Europe would likely showcase that).