Well looking our transfers and speculation id say WE ARE getting stronger, so the talk about getting weaker when rivals get weaker doesnt mean much. Kakà leaves Milan, but Diego enters serie A.
Secondly, i`ve heard a saying about serie a, something like, You need a strong Juve for strong serie A.
So even if those players (Kakà and Zlatan) leave, while we get stronger, isnt it obvious that our rivals want to strenghten also? I think some are taking this too seriously, yeah Zlatan leaves, but inter will get a load of money, and they could build a team who isnt Zlatan dependent but a good overall team.
Oh and id say if WE want to win CL, then we will make sure wc players still sign for us.
Look La Liga, its not that good league if you watch it, couple of good teams but i wouldnt say its all that good. Yet Barca has gotten stronger and won both La liga and CL. (and now see Reals response this summer)
I think you can see that the modern game is going the way of getting stronger for CL not for your own league these days imo.
MUTD, Chelsea, Pool, Barca were clearly making their transfers for better results in CL in recent years imo.