So would it make sense to sell a folding plastic shell with screen, keyboard and trackpad in it that you can bring in your bag and pull out to plug your phone into it?
This exists, it is called the NexDock[0]. I have never tried it.
Portable monitor + mouse + keyboard makes more sense to me.
But this can also be cast to a tv, for example. I assume you can use the phone itself as a trackpad. So the only extra hardware you need is a cheap Bluetooth keyboard which you can get for $15.
As mentioned in TFA, Android has had a "desktop" phone projection mode for years and it doesn't seem to have caught on. This seems to be a distro for dedicated desktop devices, I’m not sure what the point is when its main competitor would be the other OS Google already makes for those devices.
https://www.youtube.com/watch?v=67Jm8IiwURQ
That's 14 years old. Kind of crazy this concept hasn't developed more in the meantime.
I've always wanted a keyboard+screen with a slot for a phone as the trackpad. Saving any money over a regular trackpad? No. Cool as hell? I think so at least...
This form factor was tried before and it didn’t stick. Why should it be brought back now?