Bombers don't really work for a base siege, Shaggy. Not enough damage. Bombers are more for countering caps specifically, not really taking down stations, as much as we'd want them to be able to. With the way balance is handled, it just isn't feasible to give bombers that much firepower, or change the way POBs are handled (even though they should be redone completely).
On a second note:
Arguing about how many caps exist in-game is kind of a strawman argument tbh. I could sit here and question why the CR after getting stomped still has five carriers+stationary ones with their minuscule amount of resources, or even why the HF maintains five Arbiters, an Osiris and a Ranseur, but it'll never ever be as explained as we want it to be within a realistic time frame, because disco isn't really realistic. It's a space shooter with strange physics and accelerated energy that miraculously disperses in space after a set distance. I honestly would love there to be some realism, but it just isn't possible. Don't let that dissuade you from explaining how your ships are maintained though.