I know it creates a ton of compatability problems but its just so unnecesserily huge when you consider its only 8 pins. You could half the height and retain the lock-in clip functionality quite easily.
You'd have to replace the global networking infrastructure. Starting from every wall plug to the switches and backbone devices. The new connector would have to be easily crimpable, and hopefully as cheap as RJ45, I don't think you could go much slimmer.
All of this just so your end device can be a little bit slimmer. Definitely not worth it.
Using both at the same time so you could leave the backbone alone might work, but this already exists in the form of a usb type-c network adapter.
AFAIK, there's one, IEC 61076-3-124, but it doesn't seem to be very common.