If it has more resolution per mm, a smaller sensor can resolve better detail (although optics will either make it harder or easier based on diffraction and stuff I don't know enough about). I don't know that digital sensor tech is there yet, but sensor size won't intrinsically limit resolving power. Also, film grain, the silver crystals, used to be larger than it is now, so older films will have lower resolving power, and faster films will have lore resolving power. So an old movie shot on film may not have more detail than 1080p.Effectively, we're comparing capturing light on a 16mm^2 area (a mobile device) vs. 864mm^2 (35mm film or Fullframe). It's only logical that the latter will resolve a lot more detail.
What's wrong with this or this? They'd print just fine.[Which is why I'm quite skeptical that there are mobile phone devices that supposedly have 'good quality' for anything other than online sharing...
I don't disagree, although there are arguments there. Early colour film was pretty crude, for example, even if it has more lines per inch than a modern 2k or 4k digital film.It has taken a long time for digital sensors to catch up to what film has been able to resolve, even at fullframe sensor sizes. And even if todays state-of-the-art fullframe sensors do a good job - it's still arguable if they have caught up in every sense - there are still other factors to just mere resolution, like colour depth for instance.