Native PHP installers

I know what you mean. There is clearly a much larger population of non-technical users/publishers/content developers/domain owners than there are web developers. So yes, a CMS audience is much larger than a frameworks audience.

Personally, I started out using a CMS that let me start learning PHP (it was called Etomite but it died. The biggest fork, ModX is awful now IMHO). But I would never use a CMS now. Perhaps that says more about the types of sites I build than the nature of CMSs.

I think it is an interesting idea to build a CMS to promote the framework though, like ellis lab did originally. (Or perhaps they built the framework to support their CMS - not sure.)