They don't have to, it's a perk I'm sure that many (me included) rather have their employer pay/take care of, than to do it out of pocket with higher salary.
And no, we don't have the wait times Americans are afraid of. I can visit a doctor the same day and get treatment. My friends back in the US are desperately trying to find appointments with everything filled months down the line. America has the worst of all systems combined.
Americans (I'm an American) sometimes have a preconceived notion that, if something is really expensive, it must be good. No... no that's not necessarily the case.
The insurance companies would love for you to believe that, but in actuality, we're just getting fucked. It's just a worse system overall, in pretty much every metric you could possibly choose.