Very true. The 'blowback' of the FN, etc.would really move the shoulder of the casing and pushing it back with resizing really weakened that area. I could get maybe four reloads before the M&P before the neck/shoulder would split. I used to separate my fired brass by how many times it had been fired but no longer.

I have been using the same 200 pieces of brass over and over to test the M&P's Tempo system and so far no neck/shoulder splitting.
Fire - media tumble - resize - load - fire - repeat.
The ones that still have 'some' coating left look terrible but still no FT feed or fire (or extract).
Every one of them has been loaded at least ten times and because the head is so small, I have had to retire a few because the primers were getting loose.
With the fully supported bolt face and the extractor having to jump the rim I had expected those tiny rims to start failing but that hasn't been an issue yet. Strange looking extractor but I guess the design works.