I guess why I think NBA coaches are better is because, they coach the best players in the world, which most typically means the teams are closer together in terms of talent than in other leagues.
There is not logical correlation between these two facts.Erik Spoelstra coach better players than Scott Skiles,but I think anyone consider Spoelstra better then Skiles,until he proves it
I point out that in NBA you don't need any kind of test about basketball knowledge,while in europe you need it,so while there are great coaches both in europe and in NBA,to coach at lower level in NBA you don't have to prove before your skilss,while in europe, you have to do it