Ugh, you guys. This never happens. I rarely ever face 2 archers as a shielder all alone with no other teammates around, and I never play on a team where it's 10 shielders vs 10 archers. These hypotheticals prove nothing.
A shield never breaks from arrows or bolts. If they do, stop using a pussy shield and get some shield skill. You can delay archers until a teamie comes. You can time their shots somewhat while you advance on one, or line them up so they both can't shoot at you. You can use a piece of cover to guard a flank and block their arrows until they are out of ammo. You can try to bum rush them (and get shot a few times) and kill one. These things don't always work but nothing ALWAYS works. Still, in these ways, shields counter ranged.
But these scenarios rarely happen.
Usually it is a mix of 2h, cav, shielders, and ranged on the field, or in a castle. If the 2h charges the enemy ranged, they get shot very much and might die. If a shielder(s) engage the enemy ranged they get shot much less (or not at all, as the ranged usually just shoot at something they can actually hit), and they usually drive the ranged away so the 2h's can fight in peace, or they die. In this way, shields counter ranged.
On a siege map, ranged characters do 1 of 2 things. They are either on the attacking team, and trying to get the flag, or they are defending and shooting at the attackers. In both scenarios, the shielder just has to raise his shield and he can climb a ladder with impunity, or guard the flag and soak up arrows -- thus negating the ranged to an extent. In this way shields counter ranged.
When an archer is up on a wall (Attacking or defending, or in battle) sniping people, a 2h usually can't go up and get them...they will get shot while climbing the ladder/stairs. A shielder can go right up and not even flinch...and take out the sniper. In this way, shields counter ranged.
Unlike the 10v10 archers against shielders team, these scenarios I list actually happen all the time.
There are many more examples. Use your imaginations!
First of all, you stated that you pretty much only play siege. Obviously these scenarios do not happen on siege and obviously ranged in siege are countered by running past them and capturing the flag, there is no fear factor in siege and no need to kill the archers, obviously I am talking about battle.
Now on EU battle ranged groups actually often survive till the end. Often on maps there is one spot that gives a slight sense of safety to ranged, a roof, a little hill or some other type of elevation and ranged tend to band together on these locations. In general ranged tend to band together. Due to fear factor from other players for attacking a squad of ranged, they avoid this location as much as they can and rather go for safer targets. This enables the ranged group to often survive until the late part of the round. You are right, 10 shielders versus 10 ranged never happens, I have seen 10 ranged left alive on one team though, sadly the ones alive on the other team are never 10 shielders. So many times the rounds has come down to a 10 vs 10 scenario and very often the team with the most ranged wins, because nobody really knows what to do against them. Their optimal strategy would be a simultaneous charge at every ranged player, but due to lack of coordination single players get picked off because the ranged have a much simpler optimal strategy. Spread out a little, approach the remaining players and focus fire anyone that comes close to one of your ranged teammates. Crossfire does the rest regardless of shields.
You can tell me this never happens, but it does. In short, the natural behaviour of ranged causes them to survive in groups because nobody really feels like going after them and when the player numbers on each side have decreased, a high ranged concentration is nigh impossible to counter. Even if the remaining players on the other team are all shielders they still won't be able to counter due to communication issues and getting kited by one ranged and then crossfired by the others.
