Statistical failure likely has less to do with the OP's issue than consecutive failures due to the remaining tires being asked to bear more than their load capacity after the first tire failed.
If there was lots of safety margin on all the tires such that there was meaningful redundancy in the system we'd likely not be having this conversation.
In the 3 RVs I have bought so far, I have noted that there is not a lot of margin in the tires which are typically rated a little over the averaged (side to side) load the axle is expected to see. As an engineer I would not take this approach. I would make allowance for the typical overloading that the RV is likely to see, and on top of that I would add additional margin for side to side imbalance.