To answer the original question: alcohol doesn't expire, but the other ingredients (like moisturizers) might have an expiration date. In some of the products, it's not really that they go bad, just that the moisturizers aren't stable to stay in solution forever.
Many people I know in the medical profession have said that the more antibacterials we use, the more the germs adapt and become resistant to treatment, including medications.
This is true, but antibacterial soaps are the problem, not the waterless hand sanitizers. The ingredients in the antibacterial soaps work against germs in a similar manner to antibiotics (and they are what leads to resistance in germs). Alcohol works in a different way and has not led to resistance.
Many hospitals (including the system I work for) have pretty much gotten rid of antimicrobial soaps and are using just regular lotion soap for times when hands are visibly soiled or actually have body fluids on them. When we need to disinfect our hands (if not visibly soiled or after hand washing), we use alcohol hand sanitizers. That is what the newest Center for Disease Control guidleines for hand hygiene in hospitals recommend.
The antibacterial gels can dry your hands badly and causes cracks the open you up to bacteria rather than prevent it from being a problem.
They have done a number of hand health studies in hospitals and most people's hands actually are in better shape using one of the hand sanitizers (with added moisturizers) than traditional handwashing.
Antibacterial gels do nothing to prevent viral illnesses.
The waterless hand antiseptics (some are labeled antibacterial gels) use alcohol as their active ingredient. Alcohol kills quickly and does a very good job of killing bacteria, fungii, viruses.
I won't bore you with more (I am an Infection Control Specialist, so this is one of my "pet" subjects), but I did post a lot of information
on this thread if you are interested in more info.