I think Casso destroyed the Lucchese Family the same way Gotti destroyed the Gambino's, by which i mean they were not destroyed but set back. Remember that after each informant is flushed out, the pieces shift & things change. power dynamics change. The mob adapts, we all know that. I think theres always a key group of guys that dont get caught up in the bullshit & keep it all rocking along. Even with nut bags like Casso in charge, eventually the guy that kept his head down & earnt is rewarded when they (the nutbag) self destructs, as they always do, & (in the shift of dynamics) the one-time soldier/capo is elevated to Boss, having proved his ability to earn under the radar as much as possible, to "make money not headlines".

These are the type of guys that keep the Family going, & thankfully the "brain drain" in the modern mob means there's less & less such men to keep things in order & viable.