Trying to parse my way through this. Lundqvist, Shattenkirk, Staal, Smith--all have contracts that run through the 20-21 season. So your idea is to keep three overpaid veteran defensemen on our roster all through this year and maybe through next or most of next no matter if they're blocking better, younger players? In the case of Smith maybe burying him in Hartford but his cap hit for the much greater part won't be buried--maybe 925K of it. So instead of buying him out--we put him in Hartford and take a $3.4 mil or so cap hit this year and next.
I suspect the Rangers are hanging on to Staal this year. If an opportunity comes along to move Shattenkirk whether it's this year or next year--best to do it--we might not get another chance. I'm not sure Smith is in the top 6/7 organizationally of our left side defensemen. His inclusion on the roster absolutely is going to block a player. I'd buy him out.
Anyway you don't really explain why dumping these three guys is shortsighted.