I think that T.A.'s , especially those who specialize in cruising, or most any other specialties, will be a thing of the past in a few more years.
I think with the inter-net that more and more people will deal directly with the cruise lines or will deal directly over the internet with people who may call themselves T.A.'s but basically the hand writing is on the wall for the average T.A.
Those who can and do handle the longer trips aboard the luxury lines,who can and do book air, excursions, extra days with hotel arrangements, cars for you, etc. will hang on longer because of the type clientele they deal with-- but the T.A.'s who handle the 4-5- or 7 day cruises for the average Joe will be a thing of the past before too long.