Originally Posted by
Loose rivets
I assumed you meant load bearing wheels under the pods. I'd given thought to such a thing, or skids, under the MAX 8 pods, but there's really nothing there to take the impact of a heavy landing, let alone a wheels up landing, however momentary. It's very exposed vulnerability, like heart and lungs under a wisp of a ribcage.
It will be interesting to know exactly what stopped the engines. Perhaps nothing more than bent pipes.
The whole gearbox is right near there, with a very high rpm drive shaft turning it. It may have disintegrated with the impacts.