I can assure you it's linked. the league YOU play in will be more competitive, not saying that the others won't be, but you'll see considerable difference in results and tables of any league if you are managing in there compared to when you manage elsewhere and simply browse through their results, whether it's quick sim, or detailed results.
only in epl if you observe, say you manage Liverpool, Crystal Palace very much might be your bogey team, coz IRL they have messed up with Liverpool's results.
winning comfortably against Newcastle playing as Arsenal? don't sit back, remember the epic game from two years ago!
there are certain results that would be inherently biased against your team given how your team has fared over the last few games IRL.
just an example while I was managing in a lower league, the following was what happened in various other leagues.
http://www.fm-base.co.uk/forum/foot...968-titan-oliver-kahn-back-7.html#post2807650
as you can see, if you were to manage in any of those leagues with any club, were you to finish with the points the winners had in those leagues, there's a very good chance you wouldn't have been the winner then.
that's what I have observed over time.
Also, Barca and RM have a connection in game. If you play as either, and go without making any big signings for a while, your rival would also do likewise, but were you to bring in big signings, the other team would also spend big!