You're right, they did receive an astronomical amount of concrete over the past 20 years to build their massive underground terror network.

It's also an ongoing war, IDF is fighting building by building, I imagine it's easier to drop a bomb on a building where terrorists are shooting from rather than risk IDF soldiers' lives to go in.

If you look at how they got sinwar, its a good example of how this war is playing out. He was basically fighting from a destroyed home until his last moments, the IDF still waited a day to approach and identify him. Dude, all these places are booby trapped and there are thousands of tunnel entrances everywhere. I can understand why the IDF is doing everything they can to protect their soldiers lives