That works out to $200k/year for each employee, which after you account for benefits is a solid middle class income, assuming they don't live in downtown San Francisco or something.
The traditional distribution of social classes historically was something like 90%+ working+lower classes (farmers/craftsmen/factory workers/service jobs/soldiers/etc) 9% middle class (merchants, doctors, lawyers, officers, scholars, managers) and 1% or so of upper class (landlords, aristocracy and capitalists; CEOs and politicians). Middle class grew much larger in mid-20th century USA, exceeding 50% but perhaps that's just a temporary situation that's now reversing as the inequity has been significantly increasing in the last 50 years or so and it looks like in the future middle class might be a minority forever - IIRC current stats would be something like 1-2% of upper class, 45% middle class, and the remaining 53% or so working+lower classes.
If you look at social class stratification, the general assumption is that if you have to work a job for your income, you're not upper class, you're serving in the employment of the upper class. If you have a high paying job, that's defined as "upper middle" social class at least until you have accumulated wealth to transition to a capitalist/owner/investor role (as some popular musicians and athletes do); being in the top 4% of earners is quite reasonable for traditional upper middle class roles e.g. independent lawyers and doctors, which also tend to earn 200k+/year in USA.
It's among the top 4% of income, that's an objective metric. Being in the top 4% of people in one of the wealthiest countries in the world is objectively not middle class.
I don't think you've been keeping up with home prices and insurance costs around the country. $100k take home isn't all that anymore. You're not food stamp poor, but it's easy to be house poor at that income level, especially if you're shooting for a better school district. Health insurance costs eat up so much of that it is not funny, even if you are healthy. If you or someone in your family comes down with an expensive medical condition you'll be in real trouble.
True, these people are all self employed, so insurance costs would be pretty large. If you're making 200k I'd still say you've probably got at least 100 left over after taxes and insurance. That affords you a 600k house using the 30% of income rule if you can get the down payment together.
It's basically a regular job at that point.