Doing it yourself? Good luck! Hope you've got good service on your phone where ever you happen to be when things go wrong.
90% of travel is probably happening where mobile networks are available. Also, since most travel seems to happen without travel agents today, it appears that "luck" is not that necessary, otherwise people wouldn't be choosing to forego travel agents.
Travel agents were not outlawed. Most people just prefer to save money and do the work themselves (for most trips) rather than pay a travel agent.
Yes, but they're already one level up, so they can fix the problems in their company's immediate system, and then unlike the customer, they're a trusted party in the network of all other parties, so they can mail/call other parties directly and get people there to fix issues without too much delay.