Trapping and/or shooting from the ground would be far more efficient, and far less expensive.
I don't know anyone trapping or shooting 450 from the ground in 2.5 days. As for the cost, it is quite expensive, no doubt, but if people are willing to pay to fund the pursuit as a tourist industry, then why not?
I have only spoken with a few folks who have been helihunting and all killed more hogs in one half hour session than they had ever killed on a given hunt.
It may be a gimmick, but one that yields typically much higher returns for hunters than they ever experience anywhere else. As a professional hunter, Quaca probably hasn't eradicated as many pigs so fast while hunting and Nugent probably has not either.
Heck for all of 2012, the good folks over at Texas Hunting Forum only took 2067 hogs. Most of those folks are your average occasional weekend or holiday hunter/trapper.
Given all the folks that hunt hogs when they can, most only manage a few hogs per year. That they can pay (through the nose) and take more in half an hour or an hour than they probably would take all year long otherwise is a big improvement. Heck, and given what some folks invest in going on hunting trips, a helihunt cost relative to pigs yielded may actually be economically more efficient than going on a whole series of hunts throughout the year to get the same number of hogs or less. Time-wise relative to hog yield, it certainly would be more efficient.