There are 535 Congressional seats, over 7000 state legislatures seats, 50 Governors, numerous other state offices (Lt Gov, State Treasurer, etc), and tens of thousands of local government offices. While POTUS is the big one, it is not the only office that the Liberty Movement needs to be concerned about. So if Rand doesn't run in 2016? So what - there will be plenty of people at the congressional, state and local level that will need support.
One cannot control what goes on around them, we can only control what we ourselves do with our time and money. Those who are committed to full time grassroots activism can do what we know works. Show up at meetings, run for committee offices, support liberty minded candidates as they run for office, and work as hard as humanly possible in our own backyards.
While I can appreciate your concerns for the "what ifs" of the future, many of us are focused on what we can do right now. We have a lot of great candidates running for office this year (Cruz, Bills, Kerry B, Amash, Massie, etc, etc, etc) - these folks need money and volunteers.