OFDM connoisseurs: what is the bandwidth-to-width ratio?

Question

WiFi

Greetings.
Maybe it's complete nonsense, that's why I'm asking.
802.11ac achieves 433Mbps at 80Mhz channel width with QAM-256 modulation using 242 subcarriers (=8 pilots = 234 useful ones). Given that the subcarriers are independent, is it safe to say that, say, I can get ~18 Mbps on 10 subcarriers (433/234*10)? The question is purely theoretical, reduced noise immunity and pilot subcarriers are not taken into account (for example, a radio can listen to the entire range with all pilots, but decode only its 10 subcarriers).
The point, as you might guess, is in assessing the possibility of building a MU-MIMO system based on 802.11 with subcarrier division, as in Wi-Max. It is clear that it will only work downwards, but it is interesting.
Considerations on the noise immunity of such a system and the balance "the number of subcarriers - noise immunity" are also welcome.
Thank you!

Answer 1

Perhaps I’ll say stupidity, but everything will depend
a) on the WiFi access point
b) on the client device
As my friend engineer will say, you need to take the equipment and measure it.