Take 5 drones, sneak from other directions and simply overwhelm the system. If in pair, multiply the attackers via some decoys, it becomes just a statistics game.
I can imagine this protecting some future US bases in same way C-RAM is used. But from what I read from ie Iraq veterans they had it turned off most of the time for the fear of shooting down its own planes. So much for trust in high tech if its too powerful and automated.
Chinese have some systems, but from demo I've seen the laser beam took some serious time to shoot a single missile. Drones are smaller and way more fragile (so also harder to hit) but this ain't Star trek or Star wars.
Bigger picture - if knocking the laser defense off-line slashes the unit cost of destroying bombers, then it may be the obvious first move in any competent attack.