A lot of them already are running OpenWRT. It's just not the upstream OpenWRT. Instead, it would be an ancient version of OpenWRT with an ancient Linux kernel

A lot of them already are running OpenWRT. It's just not the upstream OpenWRT. Instead, it would be an ancient version of OpenWRT with an ancient Linux kernel (hint hint). Guessed why? Yeah, the same story as Android. Hardware vendors (those actually designing wireless chips, like Qualcomm and Mediatek) based their official SDK on an ancient version of OpenWRT and piled on tons of non-upstream-able patches to implement drivers.