No need, we live in an era of drone warfare. Human soldiers aren’t even in the top 50% of most effective combat units anymore. Armed security is all good and well but a machinegun emplacement isn’t going to do a whole lot about 500 incoming quadcopters carrying thermite payloads. You don’t even need to destroy the whole bunker, just the entrance, then roll up a couple of Caterpillars and put them under a 12 foot dirt hill. And if the drones don’t cut it, say the compound has EM shielding of some sort that causes them to stop functioning (a feature that many modern actual militaries don’t even have), a private plane shoveling a couple hundred pounds of explosives out of its cargo storage from cruising altitude would probably be a suitable replacement.
No compound of any sort is infinitely defensible from superior numbers. Zuck/Musk/Bezos/Etc may be rich but their reach is not limitless. Just like how civilians aren’t going to want to rush down a mercenary emplacement, pretty soon all the available mercenary forces are going to be thinking twice about signing on to defend a compound where disposable drones like to drop random pipe bombs from the sky every other day.
In an end of the world scenario, where safety exists only inside the bunkers, the bunkers will fall, and swiftly. In a scenario where safety does exist outside the bunkers but everything generally sucks, and the Rich inside the bunkers are still able to be seen or have news posted about them, the bunkers will fall eventually. In a scenario where the Rich disappear into the bunkers and are never heard from again, fuck 'em, mission accomplished, we don’t even need to raid the tombs.