A state of the art $10K cartridge on a $500 table/arm or a good $500 cartridge on a $10K table/arm?
Now that I think about it, I actually have everything here to make almost this exact comparison: Origin Live Sovereign turntable with Origin Live Enterprise arm is very close to $10k. Koetsu Black Goldline is not a $10k cartridge but is a pretty darn good cartridge all the same.
My vintage Technics SL1700 is also very close to your hypothetical $500 turntable. On it is a Stanton 681EEE which is quite a bit less than $500.
So not exactly what you said, but pretty darn close. In this case it is no contest. I am not about to move the Koetsu to the Technics, not unless you get off your hypothetical you know what and make the trip here. But if you do and if we do I will bet you your next paycheck against mine you agree the table and arm make the biggest difference.
And I hope you have a lot of OT on your next one because I sure have a lot of OT on mine!