FormerlyHemlock
Hero
I don't want to single out any one of the replies saying this so no direct quote, but
"meat shields is easy, a ranged fighter can just switch to melee"
I need to ask y'all why I read this over and over again. I think I have said it many times, but all the thinking archers are squishy is outdated in 5e.
A character does not need to switch to melee.
Just keep firing crossbow bolts completely unhindered regardless of whether the monsters are 100 ft away, or if they surround you completely.
No squishyness. No need to switch to melee. No drawbacks, penalties. Completely unhindered steady stream of bolts.
Sure, to me this is a Flaw that needs to be fixed. But the first step towards recovery is insight.
As long as you think of how ranged combat worked in previous editions you can't see the problems with how it really works in 5e (assuming feats).
Since you ask--it's because switching over is (sometimes) more efficient. Let's say you're in a stone labyrinth or something, so your front line is only 2'-4' wide and you only need one PC to hold it while the others make ranged attacks. If that one PC is in archer configuration shooting arrows, he has full damage output. If he instead puts on a shield and Dodges, the party's damage output drops by 25-35%, but the monsters' damage output drops by 40-70%. (Depends on the monsters' to-hit and the new tank's AC.) The party comes out of the fight in better shape if the guy in front tanks instead of shooting.
Ranged specialization does not preclude functioning as a tank when needed.