D-Bus is over 20 years old so a reboot is in order. All this guy's gripes are not legitimate, but many are. However, upgrading desktop infrastructure is just as much about influence (clout) and "social" excellence as it is about technical exellence. A new ipc mechanism that is not backed by the major players has no chance.
I'd argue vaxry _is_ a major player, what with the rise of omarchy.org and r/unixporn, popularizing hyprland enough for him to have enough momentum to publish standards for this new era of TWM linux desktop.
Being a major player in the Linux desktop community is what drives success for these sorts of things. And he's not there right now.
For the most part, there's a large ecosystem split between tiling window managers and everything else, and the former is super-tiny in terms of desktop developer reach.
Even within the already small Linux desktop community, the user base of omarchy and extreme customization ('unixporn') is minuscule. The narrative of omarchy or even tiling window managers 'taking over' the desktop world is largely a hyperbolic delusion perpetuated by YouTube influencers and tech bros. For most of them it's just a performance if you watch them struggle navigating it in their videos. The omarchy release video is probably the best example.
Honestly, who cares?
This will no doubt be used by many people who use Hyprland and I really don't think Vaxry cares about anything else. He's a college kid from Poland who now is getting enough donations he probably will never have to work for someone else if he doesn't want to, and can just continue developing his own ecosystem.