Good observation and analogy.
One thing to always consider - many of these people run for President for reasons far less noble than actually being President.
-- They raise lots of money - don't spend it all - and keep it.
-- They face other campaigns down the road (House, Senate, et.) and want to raise their exposure.
-- Simple resume padding for the "speakers tour" - i.e. higher fees.
Running for President is easy - being serious is not.
OR to get a VP slot