> Which means that there will almost certainly suddenly be a lot more "workers".
You mean a low unemployment rate?
> Your system relies on taking away a great deal of money from rich people... the more you do it the harder those rich people are going to try to avoid paying
Not really, no. Money in excess of $90k isn't confiscated, it's still used to purchase status just as it is today. The only difference is that it's purchased from the government instead of BMW, De Beers, etc. Status markers are essentially arbitrary anyway, why not just have a single number? It's much more efficient.
> suppose that every employer that currently pays anyone $(90k+x)/year decides to pay them, say, $(90k+0.1x)/year
They could do that, and it would lower everyone's rank. This would cause some people to quit those jobs and find other jobs that offered more status, lowering supply and causing the price to go up again. If salaries drop because of market forces, the savings would be used to invest in the business: hiring other employees, improving operating efficiency, R&D, etc.
> they also want to get rich because wealth brings large houses, etc.
Any income above $75k doesn't contribute to personal happiness, and standard income is already 20% above that. Luxury goods don't contribute to happiness, they're just a wasteful and inefficient way of signaling status. That money that could be used to improve lives or fund innovation.