Yeah, I agree with ya'. I was playing both 4's and 5's, and switching whenever the song called for a real B, then, my choice of basses was determined for me. I switched to 5's out of necessity, my gear got stolen, and I could only afford to replace one bass. That pretty much meant I was going to be playing a 5er. That was years before we formed the band I'm in now, and I've been in this band for 15 years! Same type of schedule, 100+ gigs/yr(plus we've already booked most of next year!), and almost all of that has been on a 5er. I've had a few 4's over the years, but I never really played them. I'm so used to playing 5's, that 4's just feel bizarre. BUT, I just ordered another 4-string, because of my one issue with playing a 5er...
Dropped-D.
99.8% of the time, dropped-D on a 5 is simple. It may require some finger gymnastics(I like to use Slither/Velvet Revolver as an example), but it's very doable. That other .2%, can't really be played any other way(Killing In The Name/RATM)but in Dropped-D, and, to me, Dropped-D sounds better on a 4 than a 5. Sure, you can tune to Dropped-D on a 5, but it just doesn't sound the same and there's that extra string that you're not gonna use...
Still, if I was gonna pick one bass to play "bro country", it would, without a doubt and in no uncertain terms, be a 5er...