Team based games have had some sort of spawn protection since team fortress, quake, tribes, unreal, etc.
The big empty barren spawns were a concern from the beta. It's not really a case of it being "too late" to fix this, because if LBI was still a round, they'd still be ignoring these much needed fixes. They were ignoring them since the beta.
There's a million ways they could have implemented spawn protection, but that wasn't their vision. They wanted a "blank canvas" the players built on.