I think it’s better to think of it like this:
How do you make your money? Do you need to make a wage? Or can you let your property (land, buildings, stocks, etc.) be your income?
The real amount doesn’t matter, it’s whether you have to work to live or not.
If you have to work, you are the working class. If you don’t, you are the owner/capitalist class. But your analysis is still somewhat correct: millionaires and small business owners are closer to the working class than billionaires, it does still matter how they make it though.
I think I generally agree, yeah. There’s something to be said too for if your money is made by owning or by maintaining. I don’t give a shit about landlords who rent shit out and do nothing else, but I think building administrators who fix issues and handle maintenance are probably working class.
Comes back to what you were saying. Do you make money through labor, or through ownership?