You have a point about how silly it is to scrimp on ethernet ports in new construction/remodels--wifi with a wired backhaul is unquestionably preferable to pure mesh.
But to say "wifi has nothing other than mobility" is purely asinine. It's like saying that planes offer nothing over cars except the ability to travel faster--yeah... that's kinda the point! Compared to the number of networked devices in the average home, there are very few current or near-future devices that could leverage even a gigabit connection fully, let alone justify a dedicated wired connection.
Streaming video needs a few 10s of Mbits tops, security cams are similar, streaming audio needs a fraction of that, your smart home devices & hubs are negligible, mobile phones and tablets downloading 100MB apps barely even blink at current wifi speeds. Even the average WFH-er is going to saturate their company's VPN before their wifi connection struggle.
Is an ethernet connection technically better in some of those cases? Sure, but the vast majority of people would notice no functional difference aside from having to plug in a second cable.