Comments of chapter undefined of Dungeon of Pride, Laplace

The way it was phrased made me believe that they were conquering , aka destroying the dungeons. The guild leaders of the top 5 guilds occasionally remark how they have dived and conquered numerous low rank dungeons. Correct me if I am wrong but destroyed dungeon cores are extremely precious. So if an adventurer was able to defeat a dungeon he would definitely smash the core. So how would they repeatedly and with easy dive down in so many dungeons without destroying the core and constantly reduce the amount of dungeons. Unless there is some kind of treaty that prevents them from easily destroying a dungeon core but with some exceptions