Because teams in win now mode don’t have $7.5 in cap space to take a risk on a guy who hasn’t been healthy in a very long time.
If you are going to take a risk like that and give up assets, the cap hit better be low.
I tried to walk you through your own thoughts and clearly it's not working.
You claimed Tarasenko is not an asset. The fact is no team in a win now mode is going to acquire a player who they feel can't improve their chances of winning. There's no amount of salary retention to turn a player from a non-asset to an asset.
Florida isn't going to say well we don't like Tarasenko and think there's no possible way he can help us win more than our current roster but,,,,, if only the Blues could retain 4 million dollars that would turn him into a player we really think is an asset. It doesn't work like that.
Teams can and do retain salary from time to time but it doesn't magically make a player better.