I was pretty dang sure I'm made that way. Don't get me wrong, I love to sing the harmony because it makes being a soprano more interesting but I still can't dip below the treble clef any easier than an alto can belt a high F.
I actually suspect the altos trying to hit a high F would have an easier time of it.
I took voice lessons very briefly in college (about a year total). Prior to taking voice lessons, I had a very small range, and was a very decided alto. By the time I stopped taking voice lessons, I was singing more like a mezzo soprano. In other words, I could hit very high notes, but it was extremely difficult and uncomfortable for me, and I wasn't always consistent about it. On the other hand, if I had continued to take lessons and practice, I might have been able to build my comfort level at the top of my range.
But at some point, it's just not possible to sing any lower. I call myself an alto because my lowest singing notes are low, not because I'm incapable of singing high. My favorite songs on the radio to sing along to are almost all sung by men, and I'm not even singing an octave up to manage it.
Personally, I think the first soprano (or soprano, period) being the "better" part in the minds of some is for the same reasons why the first violin section (or violins period) is "better" in an orchestra. Both have highly visible parts, either because they are hitting the highest notes or have the melody line (or both). But anyone who is going to perform as part of an ensemble has no business coveting other parts to the point where they screw other people up. Sometimes, in any given piece of music, you don't get to have the most fun part. The trick to enjoying it is to find what is fun about the part you do have, because 95% of the time, there's something that's legitimately pretty awesome.
Unless you play the cello and it's Pachelbel's Canon. Then there is like negative eleventy million awesome. Times three, since everybody else
gets at least a little awesome, but you get the same 8 quarter notes for like 10 minutes (which, of course, feels like approximately the rest of your life).