* Majority of packages in Fedora are now maintained by volunteers
* Longer lifecycle in Fedora isn't going to reduce the revenue stream anymore than a free rebuild of RHEL itself would. The revenue model is commercial support and service agreements and not just the software itself. Otherwise, there wouldn't a chance against hundreds of free distributions, some of them with relatively longer lifecycles.
* Fedora is upstream or the basis of not just for RHEL but several other projects like OLPC or Moblin. OLPC's latest build for example is almost 100% Fedora. Whatever improvements made is pushed upstream aggressively and benefits all the other distributions as well.
* Considering point 1, even assuming what you claim is true, it wouldn't necessarily matter. Other organizations have been sponsoring infrastructure as well and all of it by policy free and open source
The actual barrier if anything is going to be the amount and nature of the work required and people in the community willing to do that. I have signed up since the proposal seemed more reasonable this time. Let's see if there is enough momentum to take it further.