802.11be looks like a nice approach to scale wireless networks horizontally.
What about ax200. I have three RBM33G boards with two of this radios per each board. All radios are connected through m.2 <-> mini pcie adapter. iwlwifi driver see both radios and let play a little bit with them. So it's possible to run m.2 wireless modules with cheap MIPS boards (about $35).
1x PCIE 1.0 for all radios looks like a bottleneck for such configurations, but additional testing required.
Anyway, it is possible to build low-cost dual band 802.11ax router.
P.S.
Wireless throughput is growing faster than embedded CPUs are getting cheaper.
Best regards,
Kirill Lukonin