Honch wrote:I have even read (I am trying to find it on the internet now) an interview
Hm, not sure how reading about guitars tells you anything about playing guitars.
At least with hardtail guitars, just string 'em up properly - with the right technique for winding the strings around the pegs - and you'll find out they stay in tune pretty well. Nylon may take a little more to settle, but afterwards it's as solid as the others.
You just check the tuning before playing, and you're set. If you are having tuning issues, there's something off in the peg windings or the saddle.
Most "tuning" issues that people experience when playing even a half-decent acoustic aren't about the guitar at all, but about their technique - inadvertently bending strings, pushing too hard and unevenly, bad barres, fretting notes in the wrong spot, bad picking or finger control and so on. Since acoustics tend to have slightly larger necks, thicker strings, and no crunch, distortion and reverb to hide errors, the player's technique is more important, there's just less to hide behind. You can tell a good guitarist in the first three seconds after handing over an acoustic guitar.
Nothing really special or inevitable about it: nobody's born knowing how to play guitar. so, so long one realizes that the issue is most likely in one's playing, it's just to start looking at the fingers and practice til they do it right.