writing software is about writing the hard-to-write parts one time, so that users aren't confronted with the anomalies all the time. Computers are our servants, we need to let them figure things out for users, and take care of the headaches, not simply declare "here, this is a headache".

yes, what you are pointing out is the challenge. solve it, don't slough it onto the user.

However, the same app can appear on different sized screens with different skins, it doesn't have to be a different app.