Hard to tell why they felt the need to introduce this nonsense all over again, but I think it has less to do with hubris but a lack of research. It shouldn't be hard to find out why these things didn't work, yet they probably didn't pay attention and just went along with it. It is baffling how many mistakes they repeated in this game, things they should have learnt by now...
The COH3 snare system is different to the COH2 one. In COH2 snares auto engine-damage on vehicles if the target HP after explosion was less-than-or-equal to 75%. In COH3 that number is 50%. Snare damage above that value only results in a crew shock like effect that wears off after a few seconds. However, no doubt to punish reckless vehicle use, two snares going off successively will always result in the engine damaged status. Successive being that the yellow shock symbol is still active when the 2nd snare explodes.
tl;dr: Snares on Falls, Mandos etc. are mainly for self-defence rather than crippling vehicle use.