OK, you plug a power supply, two laptops, and three monitors into a USB-C hub. What happens?
Any kind of bus where peers can negotiate protocols is going to have severe usability issues. Just look at the MacBook that's plugged into itself: https://photos.app.goo.gl/G2PivEo1JrKKtA9W6
Given the fundamental usability problems of USB-C, I don't think there is anything anyone can do toward making a simple USB-C hub.
Any kind of bus where peers can negotiate protocols is going to have severe usability issues. Just look at the MacBook that's plugged into itself: https://photos.app.goo.gl/G2PivEo1JrKKtA9W6
Given the fundamental usability problems of USB-C, I don't think there is anything anyone can do toward making a simple USB-C hub.