While some people might be overreacting to the emigration of Josh Childress (I've actually seen more instances of the opposite reaction), and despite my post yesterday, I don't think we have too too much to worry about yet.
I'd liken this situation to a watered down version of the big signing of David Beckham last year by the LA Galaxy. With the institution of the "Beckham Rule", a lot of people expected at least a few more big names to eschew their European clubs and sign with MLS teams for fat contracts. However, we saw anything but an exodus since then, with the Designated Player Slot only being utilised a total of 8 times since its inception, and mostly on guys like Claudio Reyna and Luciano Emilio: solid players, but by no means stars (kind of like Childress).
The reasoning behind this is that, though all teams are allowed to spend that kind of money on players, only a select few have the money available and want to use it. Sometimes, you play in a small market and just don't have the revenue to justify such a signing. Sometimes, you might not feel comfortable having one player that's worth several times the rest of the team combined. Moreover, on the players side, not everyone would agree to play in an inferior league just for the money, they have pride and their dreams on the line too.
Similarly in Europe, there are only a couple teams that would be able to shell out NBA-sized contracts. The list probably includes Olympiakos, Tel Aviv Maccabee, Benneton Treviso, Tau Ceramica, Real Madrid and CSKA Moscow. Other teams in Europe might have room for one mid-level exception type contract (like the one that Carlos Delfino got from BC Khimki), but those are limited too. So that might amount to a maximum of maybe 15, mostly marginal, NBA players playing overseas at a time? I think we can deal with that.