That’s basically the Neo.

Apple did patent a design for a dock in a monitor for a portable device to slot into. It’s gotta be getting close to expiration now. I think the trick is heat dissipation.

My friend who is a macOS programmer years ago had an idea for a startup mode for iMacs where instead of just being a screen, the storage and video card would also be accessible over the thunderbolt bus, so you could plug a laptop in and have multiple video cards at your disposal.