The neat part is there isn't a good way to retaliate. These players by now are gone from the corp, as is the money, so they can't do anything directly to them anymore. If they were "burner accounts" they might never know who did it. If they identify the players and they belong to some collective they could attack that collective but at that point it will probably be seen as petty and getting laughed at might be more trouble than it's worth. These heists are seen as cool for the most part. They could try to stage a counterheist, that would be exciting but very difficult to pull off.

Overall 2 trillion ISK isn't that much in the grand scheme of things for a mega-coalition like Pandemic Horde.