Yup these guys don't hold the cards at all...
Winning means EVERYTHING especially for a Canadian team. You just can't dick around with your star players regardless of whether or not you believe they deserve the money they are asking for. You can say no other GM will offer you that money on the open market, but as an Owner or GM would you want to take that risk? Especially with arguably the best goalie in the league?
But let me be clear, I agree with you and others that these contracts are ridiculous, but these are your star players and you are playing a dangerous game if you play hardball. You run the risk of letting them walk and then you're back to square one all over again with no #1 center, which they didn't have to begin with, without your top prospect because you traded him for a winger and now have a mediocre prospect pool, and now without arguably the best goalie in the league anymore. Try selling that to your fans in the most pressure filled market in the entire NHL.
And you're right about the fact McDavid being an RFA decreases his leverage, but the fact that McDavid practically brought your franchise back from the graveyard means he can and does hold all the cards. I'll give you Draisaitl because you can make an argument he gets his points because of McDavid.
I think a lot of teams, including the Kings, are well aware of the risk associated with these deals, but are probably pressured into keeping them because the team is better with them than without.