The answer may simply be that no one has the capital to launch this program today, but I hate going on long trips and watching my ticket wallet get progressively tattered and torn over the course of my trip when it would be so easy to encode everything on 1 smart card that I could reuse from flight to flight (a natural idea would be to use my FF card).

Checkin would still be required, but everything would be encoded on a durable card, useable even if network access weren't available (allowing flight operations to continue even if links are broken. Furthermore, security stations could use card readers to automatically validate that the pax is checked in and ready for their flight (see the discussion in AA of LAXT4 security changes), and in baggage claim, a reader could be used to validate that you are picking up your bags.