It was about 50 years ago when the "ply-rating" meant something on bias ply tires. 6-ply was considered stronger than 4-ply.
We have moved on to radial tires. Super strong steel belted thread area - soft, textile cord (vulnerable) sidewalls. Off-road reqires strong sidewalls.
I know from first hand experience that an unmounted BFG 3-ply sidewall tire has softer sidewalls (quieter, more comfortable) than the early Goodyear MT with a 2-ply sidewall (strong, inflexible, loud, uncomfortable). And the 2-ply GY was less prone to sidewall punctures than the 3-ply BFG.
Now, the GY MT (2-ply) has been replaced by the GY MTR (3-ply) and it is supposed to be even more puncture resistant. The BFG has retained its 3-ply sidewall and has improved considerably in durability.
Main thing I wanted to get across was, that the number of plies does not tell you anything. Are three very thin (flexible) plies stronger than 2 very thick plies? Depends on the materials unsed. Could be - but no guarantee. 2 Kevlar plies would probably beat 3 nylon cord plies.
Goodyear could have built the new MTR with only 2 plies, as strong or stronger than BFG's 3 plies. They decided to use 3 plies more as a marketing tool because too many buyers just go by numbers and the "3 must be better than 2" philosophy. Duh!
Harald