A few of those seven are cannon fodder every year, regardless of who makes it in, so it's indicative of maybe five sides, which tend to be the same every year. So I'd say that these coefficients rather speak to the width and longevity of a league's top and I would still maintain that they say next to nothing about the rest of the league, especially the bottom half.
Except if you let the non-stop team face each other competitively, I don't think there is any measure to meaningfully compare leagues. The best you can do now, is simply watch a lot of football and base your judgement on that; but that's also difficult, because countries have different approaches to and trends in their football. It's hard to say how they would really measure up if the teams would really face each other.
Oh, maybe transfers are a proxy. The best leagues might be where good players most tend to and want to go - on all levels. In that sense, I'd put the EPL on top. That's also a matter of money, of course, but if having more money attracts better players, then the point remains. This isn't just about top players; good players (the tier below the best) from the Netherlands, for example, tend to go to low-ranked clubs in England, but to sub-top clubs elsewhere.