In Summary

 The requirement of different skills and knowledge becoming necessary at differing times throughout the exploration and develop phases of interplanetary colonialism coupled with specific character traits will determine who will go for the foreseeable future.

Money and the desire to go will not be enough to be a valid candidate for a spot on a starship any time soon; however, this does not preclude individuals wishing to be part of this future from being useful to the colonization process while remaining on Earth. 

There will be many areas requiring such people as noted in the colonial model and all people involved in this model will eventually have the opportunity to transfer off world. The model as shown below (and elsewhere in this blog) has two main parts to it; Earth based functions with identical functions off world.

Colonial Model