I think those vouchers are good for 12 months from date of original ticket purchase, which is generally long enough for someone to plan another trip if they want to, especially a leisure traveler. So 70% of them not getting redeemed would indicate a lot of customers not returning for what they fear is more of the same. Since the vouchers are only given out when things go wrong, it appears that for many customers that had their travel plans wrecked it isn't worth the risk to try again. Travel blogs and the AAY facebook page often have comments from AAY passengers saying that various airport personnel such as agents at nearby ticket counters, airport "ambassadors", the airport information counter lady, etc all tell inquiring passengers that it is fairly routine for AAY to have canceled flights, hours of delays, long wait time for baggage to be placed on carousel, complaints about AAY employees not giving professional customer service, etc. The AAY reputation is not so good according to many of the people that work at the airports every day and see the big picture. I've got a retired friend that works as an airport ambassador at the ICT airport and he confirms this general feeling among the folks working at the airport. He said even the airport security officers talk about it.

But hey, you can fly 1200 miles for only $49 and often get there on the scheduled day.