Consideration of any other angle beyond this is irrelevant. Edit....the biggest thing for me, which you haven't mentioned, is the risk of losing the player and the time and money invested in said player. Your argument related to cost and insurance, etc. is good, but for me, I'd be more concerned about losing franchise player that I thought I'd have for another 10-15 years.
Yes, yes, your very clever.
To be clear, there are two separate angles that this needs to be considered. First, the health insurance aspect and the fact that the team is on the line to foot the bill if the player get's hurt. From this angle, I understand the owners wanting the rule and can offer no argument.