I agree with you, sort of. Everyone is on that quest to look for that perfect ukulele when in fact, they probably have it in their hands. As for looking for the best strings, one must go out and find what strings sound best on your ukulele. I don't think any on set of strings would sound amazing on every ukulele. No J71, no fluorocarbons, no nylons, no anything. So I think the journey to finding the best strings is legitimate.
But "best" is subjective. Everyone has their own tastes and what sounds nice to one player may sound unfavorable to another.
So in your case, you might be satisfied with your ukulele's performance and feel that you have no need to look for another set of strings or another ukulele, and that's perfectly fine. As long as you enjoy playing it and loving it, then that's all that matters. You are right to say that each flaw or deviation make one's ukulele unique.
As for cheap ukes sounding bad... it's a give and take situation. I always read people dissing on Hilo model... 2526... or something like that. No question about it, it's a crappy ukulele. But overall, once you start playing and getting better, it's not all that bad. I can play parts of piano forte, which I learned on my KoAloha(LeeLa), on my Hilo and it sounds... okay. I did change the strings on it, and that makes a BIG DIFFERENCE! I mean, it's no Hawaiian "K" model ukulele, but in the end, I would say that music is music. But as you said, any ukulele can sound great in the hands of someone who knows what they're doing.
LeeLa, as beautiful as she is, is wonderful as an instrument and I would never dream of giving her up. But... that doesn't mean I don't want more ukuleles like her. It's a passion that perhaps you just haven't reached yet. But perhaps it is better for your bank account. :music: