It's a bass forum thing, not a real world thing. A lot of guys on bass forums love to talk up flats, but rounds outsell flats many times over. A few years ago I talked to the production manager of one of the large string makers who indicated that the ratio was about 30 to 1, at least with that company.
Flats fans always claim that flats last for years, but that's misleading. For one thing, flats don't have the high overtones to begin with, so naturally they don't lose them. Also, metal fatigue happens in all strings under tension, regardless of the outer wrap, and eventually the strings can't be intonated properly. When somebody claims he's had the same flats on 25 or so years, then either they've only been lightly played (or the bass was stored for years), or their intonation is off.
The only players I know who go through rounds quickly are guys who want their strings to always sound as brilliant as when they're fresh out of the package, and guys who sweat a lot or have acid sweat.