I understand why the OP takes better pictures with a simpler camera.
On the one hand, he uses only the "normal" focal lenght. According to someone or some study I read somewhere (a very precise source reporting, I know :confused

pictures which were taken with a "normal" focal lenght sell in a bigger proportion than those taken with other focal lenghts (wide, or tele). This is probably because normal focal lenghts have a more "natural" appearance.
Now I understand that sales in the stock world and beauty or art etc. are not necessarily the same thing. But people buys images that they "like". The theory here is that the wide availability of wide and tele range, maybe in the same practical zoom, availability which is obviously exploited by the photographer, diminishes the percentage of "normal focal lenght" images, that is of those that, in principle, look more natural to the eye and therefore have more probability to make a scene pleasant.
Old fixed-lens cameras force to use only one, normal focal lenght. That is one reason why the OP, in my opinion, finds a higher numbers of keepers in his production. It's maybe a world phenomenon. Normal lenses yield a higher percentage of keepers.
I think this also had to do with the fact that, in examining a scene, he only analises it under only one "perspective", that of the normal lens. If you have a zoom, or many "primes", you begin analysing a scene under all the several possibilities, the different perspectives, focus plans effects etc. that the scene can offer with the various lenses.
But we are not computers. My feeling is that we cannot grasp the potential of very many possible compositions that all the focal lenght can offer us, maybe we don't have, or don't take, the time it takes to think to all possible options. When we have only one focal lenght, we mentally explore better all the limited possible options. We go round with a "frame" in our head. It's easier to recognise a good photograph, to "match" a scene with that one, single "frame" we have in our mind.
If we go round with multiple focal lenghts, we walk and look around without any "frame" in our mind. We think the frame will be suggested by the scene in front of us, that we recognise the scene and "instantly" apply the right focal to it in our mind. Yes, most of the time. But I am under the impression that when going round with one focal lenght I see "frames" really around me. Don't take me too literally, you know what I mean
Somebody says that to be a better photographer one should go out with one lens. That forces one to concentrate on only one kind of perspective rendering at a time, and is a good exercise in seeing "how the camera sees the scene with that lens". I agree.
Another reason, as somebody says, is that film costs. For me, this makes a difference even if it shouldn't. When I use digital, I do just like as if it was film. I think for sometime before even beginning to try to compose, I compose several times, try several angles, move a bit here and there, etc. I measure exposure "manually" (using histogram with a digital, or an external meter with film), I focus "manually", "previsualising" the shot, where will the highlights fall, where will the shadows block etc.
Well, even considered what above, when I come home I have shot more images with digital, and I think better images with film. It's something "in the back of my mind", I think. Film costs. I just ponder an image a little more without even realising it, but that makes a difference. With digital I have some kind of self-imposed discipline. With film, I have a "natural" discipline in studying pictures, a discipline imposed to me by my wallet (not an obese one).
Fabrizio