Yeah, I addressed that when I noted that teams prefer to match, even when faced with matching insane contracts like the ones Weber/RoR were offered.
There are a couple of reasons that this is the case in my opinion:
1. Most teams do not have the cap space to make them.
2. The ones that do have the cap space (e.g. Edmonton) will usually have their own RFA's coming up (e.g. McDavid). Out of fear of retaliation, those teams don't sign offer sheets.
3. In order to get a player, at the very least a small overpayment is required.
4. Using this strategy, in light of how rarely it is used, would alienate the GM from his brethren - thus curtailing his work options following his firing by the current team.
TL;DR: GMs are too scared to rock the boat.