Many times, if not all the time, squads are busy fighting. Giving them an order to build a firebase and leaving their hardly gained position is a
distraction with unpredictable results. I mean, in a busy situation squad hardly can be managed to regroup, stick together, find a truck, move to desired posistion and start building. Besides, firebases are always built at position away from the actual front line, i.e. it realy takes time for the squad to relocate, thus leaving a hole in the ongoing battle at place.
Actually, to be precise, I am talking about a tactic approach where a selected squad is "marked" as Constructors Squad and is given an order to always have a truck in hand. Always! Spawn on main base if needed, but have a truck! Not forbidden to engage enemies, but having a
building priority over fighting.
In real armies there are such special subdivisions - engineers and civil engineers. They do not fight. They build bridges, roads, etc.
Well, it depends on the server size and population momentum. With 3 squads only you can't afford to lose one, but having 6-7 squads - I think it should work.
Last note:
time is important. Practically, and plenty of examples can be provided, when commander asks some squad to build a firebase, it takes at least 3-4 minutes, even more, up to 7-8, until the SL manage to organize his people to execute the order or just to start the excution. Consider building 4 assets (2+2).
4 x 4 = 16 minutes minimum and
4 x 6 = 24 minutes average time for *initial* reaction! That's a lot of time, IMHO
Gurgul