And you can't just say 'there's lots of people for whom $200k would be a lot of money' because there's a lot of people who whom $50k is a lot of money and those jobs aren't filled either.
Short of literally offering a million dollars a year, it's got to be more complicated than how much you offer.
If there are alternatives available that use less or cheaper labor, then people will use those instead.
There's no cap for any price. And if the alternatives are cheaper, then maybe that type of business doesn't need to exist in the economy.
That's supply and demand.
The $50,000/year jobs that aren't being filled have one of:
1. Require years of non-transferable training.
2. Have insane working hours, that make your real pay closer to minimum wage.
3. In especially shitty working conditions.
4. Are in locations where $50,000/year isn't enough to live on.
5. Destroy your body after a few years on the job.
6. Have better-paying, better-work-condition alternatives that use similar skill-sets.
7. Or, more typically, two or more of the above.
That said, if it paid $200k/yr (median or even 75th percentile), the shortage would disappear post haste. The vast majorly of other jobs that pay that much tick boxes 1, 4, or both and are thus logistically out of reach of at least half the population.
I think the job has a very high incident of obesity and heart disease, as it's so sedentary, and a high incident of divorce because it's anti-social.