I completely agree with OP. In fact, I have checked the law on this and it's a giant gaping hole in the liquor laws. By design, I'm sure. The truth is the airlines make $$$ on the liquor they sell. Fair enough but there really should be a limit, especially on the vouchers. And especially in the exit row.

Planes these days can just be flying bars and coupling that with people tired from flying and driving rental cars in unfamiliar cities, we know there are cases of accidents that are tied to drinking on flights. But, the airlines are not at all regulated regarding serving restriction laws. Almost any other venue which serves liquor is mandated not to serve patrons if they appear to be inebriated, planes are exempt from this.

I've seen WAY too many passengers get served when they are obviously altered but the OP is 100% right in that the exit row should carry some restrictions on the liquor served.