Which is one of the reasons 23 out of my 24 basses don't wear rounds...![]()
I have no doubt that flats last a lot longer for you. Strings die because of hours of use, not strict calendar time. You have 23 (!!!) basses with flats on them - your time spent playing flats is spread among 23 basses. When you play rounds, it's always the same bass. If you played half your time on rounds (you probably don't, but let's play along), and rounds and flats lasted the same number of playing hours (they don't but again, play along), you'd expect to get 23 times the calendar time on a set of flats in your case. Depending on the portion of time you play rounds, etc, the math will change, but I think if you kept track of hours of use, you'd find the math isn't quite as lop sided as you think. I get a year (or more) out of set of rounds most of the time, and I play a lot, but with a few basses....the playing time gets spread around.
There are folks that do get many years out of a set of rounds - that's actually pretty typical amongst a big proportion of bass owners. Regular bass players change their strings, but folks that play bass now and then (including the guitarists that have a bass for a track here and there) tend not to - there are a lot of those folks around. I do get a few years out of a set of rounds on one bass - my fretless. As those strings are not banging on frets, they don't age nearly as fast, even though I play that bass a fair amount. The point is that, although people get a lot of years out of a set of flats, there are other things that skew sales numbers of rounds vs flats in the other direction.