I remember when Google presented their Ada(?) modular phone concept, I was really excited. But the commenters on HN were really convincingly telling me and the others that liked the concept that it couldn't happen. Basically unsolvable problem and the phone would be too thick. And right, Google immediately gave up. So it was impossible I thought. And now you see this, made by one guy I think. It was not impossible at all.

half the times people say something is impossible here on HN, what they're actually meaning is "it's not economically viable" or "doesn't make sense from a business perspective". It is not that that modular phone couldn't be built, it is that you couldn't make it in a way that made business sense for Google. There is lot of great tech there which is not used in products because of similar reasons.

Well, they were technically correct... it's technically impossible for google to do this, just like it's technically impossible for them to build an RSS reader... or manufacture a phone in this country instead of China... or (name cancelled google project of your choice)...