While opening an account with many programs might seem like a solution, it has a number of pitfalls. Especially for the flyer does not fly very, very frequently -- say less than 100,000 miles annually.
-- Generally the programs are stand alone -- in most cases, you can not transfer miles from one program to another. To redeem you need a significant chunk of miles in one program to do anything useful. Without this critical mass, you have orphan miles, miles of little value.
-- The problem with only occasional crediting to a given program, you take a high risk of miles/points expiration.
-- Most program give their elites better opportunities to use miles (better inventory) which the flyer crediting multiple programs will not have access to.

Spreading yourself thin between many programs, will dilute the benefits you will receive.