On the contrary, because of IPL at least NZ and WI young generation has taken up cricket (T20) as they see it a an earning potential like NBA or NFL outside their countries because their boards cant provide that kind of money.
If there was no IPL, then NZ as well as WI cricket would probably drowned due to lack of $$$$.
Anyway its easy for narcissistic
to blame IPL... ignoring the fact that since IPL started NZ has reached ODI World cup final twice, won test championship and performed quite well in T20 World cups. WI has infact won T20 World cups after IPL started. So wonder if blame for cricket downfall is given to IPL ,why is it not given credit when players succeed for their countries after playing IPL.
But ya blame that downfall on IPL

participation. On other hand at the same time lets also blame non participation of Pakistani players in IPL ,as reason for their T20 WC first round exit loosing to H1B visa team.
So if you play in IPL it is responsible for your cricket degrading, but even if you don't play in IPL it is still responsible for your cricket degrading.