RE: Whats been the biggest effect of 2.4 ghz
8 tracks to cassettes, cassettes to CD's. VHS to DVD's, DVD's to blue ray. Analog TV to digital TV. Copper to fiber optic. Things change. I highly doubt that you guys who think you are going to sit on your cheap 72 Mhz systems for years and years and years are going to be able to do it. As Ken says, those frequencies are going to be auctioned off eventually. It's only a matter of time before they stop selling 72 Mhz radios. The Rx's will likely be sold for quite some time after that, unless it gets banned. If the frequency gets put to use for something else, you will be flying at your own risk, and out of compliance with federal law.
I'm not saying you should go buy a 2.4 now if you dont' want to. I'm just saying it's coming. Just like VHS tapes came to an end, and everyone said "I'm not buying DVD's, they're too expensive, and my VHS tapes look just fine." Guess what. Want a movie now 'adays? You're buying a DVD.
5 years from now (or less). Want a radio? You're buying a 2.4 Ghz.
However, I highly doubt anyone will be handing us rx's for our planes. That will be our problem to figure out. Sure, they are handing out vouchers for digital TV converters but that is different. People rely on TV for everything from entertainment to safety, so they have to do that so that the poorest of the poor won't get left out, not knowing when there is a tornado warning, or who won on American Idol last night, etc. (LOL)