For mass distribution of wifi APs? Some SDN solution would have a higher upfront cost but a lower running cost. Im sure all the big providers have their own system, consumer ones include ubiquiti and omada.

Cheaper than that would be mikrotik. Not really deployable at the scale of 1000s that would be required to fit every room with a wifi AP, but CAPsMAN can scale to hundreds, so still has centralised management to reduce running costs.

If it has to be cheaper still, then any cheapo SBC with wifi. While raspberry pis might fit the bill, they would be too overpowered with too many unused features to really squeeze the cost effectiveness.
Hey, its google. They could probably fork an AP into one of their home automation thingies. Then probably a whole stack of ansible scripts to try and manage 1000s of deployed linux installs