I think the fact that 2 congressmen were on board and the publicity surrounding the disappearance was mostly responsible for driving a knee-jerk reaction from Washington.
In the late 60's and early '70's a number of airplanes were lost over the contiguous states that were not found for months, sometimes years, sometimes never. Not really any major and immediate rule changes came about from that. Even since the ELT rule there is no guarantee that a plane will be found in a "reasonable amount of time" just because it has an ELT installed (please insert exhibit A, Steve Fossett). It may improve the odds of being found but so does filing and following a flight plan. Anyway, knee-jerk reactions continue today, after all, isn't that what TSA is all about? Anytime a politician can sieze the opportunity to protect us......