While this sounds great in practice the reality will be far from ideal for the singular reason of security. The cyber issues are compounding at exponential rates as more and more devices that make things "easy" lack even the most basic security protocols and the production targets to generate revenue asap have zero to nil concern around protecting said devices from nefarious actors while in use. When the electrical and data transfer grid become one, as I believe it must for reasons of efficiency, we are certain to witness chaos and losses like never before. What you cannot see matters most! and in time many will pay the ultimate cost for someone else's 'easy'.
More like basically every electronics product uses AC. It’s a two sided market problem - there’s no demand because there’s no supply and no supply because there’s no demand.
The security aspects are solvable through various standards (eg we have LAN over power lines and coax already and they layer encryption on top to build the mesh while balancing UX). The security concerns may be the #1 concern for you but has nothing to do with market adoption.
PoE 802.3bt tops out at 71W. Not even enough to enough to run big USB-C adapter. Also, PoE is pretty lossy which defeats the whole purporse of using DC to save energy.