At $300, most lounge users most likely won't buy one.
While I see your point, I kinda disagree.
I've found mics to be an excellent upgrade path in live sound. Better sound, less messing around at the desk, less feedback. I can make SM58s work as well as the next guy, but I've found my life gets easier (and soundchecks get quicker) as my mics pack improves.
Of course, it's possible to go OTT, like I did just last night: Sennheiser e965 for vocal, Schoeps MK41/MK8 mid-side for guitar/bazouki/bass bazouki/mandolin. DIs for monitors only. FOH mix was just those mics.
Despite various instruments being played, the Schoeps mics sounded clean and natural and "right", for lack of a better word. All I had to do during the FOH check was HPF@60Hz to get rid of footsteps, and push the fader. HPF on the vocal, touch of reverb, done.
Sounded brilliant, and my life was very easy. I'm not saying that everyone should have a high-end mic for every possible scenario, but I am saying that there are tangible improvements in moving up from the usual selection of dynamic mics.
Chris