As long as there's a way to maintain the current display density, that would be just fine.

However, like on Windows, I suspect macOS would increase the tap target size on lots of the touchable elements. Even if I don't use the touchscreen, I would still have to pay the touch target real estate tax in my applications.

That's a fair ask. My dream would be a simple toggle in something like control center for macOS that can flip between "touch mode" and "desktop mode" with most of the under the hood stuff being the same and just UI changes for the task. No doubt this would create new hurdles for software devs but again I'm dreaming here. Windows 10 actually had this with "tablet mode" in the notification center but I think they already soured people on the touch Windows thing by this point. I think Apple could reasonable do it better if they had the will but they'd much rather you buy and iPad for touch and a mac for desktop and everyone who doesn't want an extra device for certain use cases is left out in the rain.

Note on Windows you can disable the touch device and it goes back to the old density. Don't know if Macs support it.