thats kind of the point though. invest resources to hold a point. you cant just decide to mobilize after reaping all the benefits of massive health pools and damage reductions then turn that all into tanks.
can you imagine how disgusting team games would be if even a single player could have the pop open to just creep emplacements forward?
Not really. They would have to pay full price for the emplacement each time they wanted to rebuild. Meaning your opponent has wasted those resources.
Not to mention that emplacements are utterly gimped these days anyway.