1. Is it because Revo is not ready for primetime?
I would not dare saying this... Revolution is amazingly powerful and flexible, and since the 2.0.0 release it has been improved and stabilized loads. It’s not a beta product (but it is getting ready for amazing features to be added in the future).
2. Is Revo not able to perform as well? And if so, where would that be a problem?
Depends on your definition of performing/performance. The backend seems slower then the Evolution one, but some features (like quick create/update) give big boosts which are not available in Evolution. I have honestly no idea how Evo and Revo compare when it comes to delivering front-end resources, but with improved caching I doubt Revo is behind.
3. Is it because people are familiar with Evo and moving to Revo is not yet where they are comfortable?
If you know all the ins and outs of Evolution, of course you would rather stay there then to start learning a different product. Although they are related, the differences can be daunting and require some more time to figure out the first time.
4. Is it because there are missing add-ons that are only available in Evo?
Revo hit PL last year.. The older codebase has been around for, what, five years? More? Of course there are more add-ons for Evolution than there are for Revolution. However I do feel that is only a matter of time, as the powerful api and thought-out workflows really challenge you to make the most of it.
5. Does Evo have a future or is it no longer being supported/extended?
Evo 1.0.5 was released just last month with hundreds of fixes. It may have been quiet in the six months before, but of course most of the core team’s resources are focused on developing and marketing Revolution. Evolution will be supported and developed for as long as there is a need for it. Revolution is no replacement for Evolution, it’s its big brother and they can co-exist.