Yes farming land yourself will always be much more profitable money wise. The program wasn't designed to give people as much as they would get from farming. Renting land right now with crop prices so high is a little more profitable then CRP in most cases, but taking a look back into the history of crop prices will prove it hasn't always been that way. Some of these people who are getting double the rental rates are getting well over $200 per acre. It wasn't too long ago that crop prices were so cheap they were hardly worth planting it seemed. CRP really saved some peoples butts then. Rent prices are high now but when crop prices go back down so will the rent prices.
Also, some CRP practices will drastically improve your crop yield and prices. For example, the CP33 program is designed to be planted just around the border of crop fields, where crops readily get shaded out by trees and yields are usually very low if any at all. In this case, you will be getting way more from CRP payments then you would if you were farming it.
As far as the not getting accepted part, you must be referring to the general CRP signup which is competitive, and you are right not everyone will get accepted. If you do it right (scoring wise) there is a good chance you will though.
However, there are many CRP programs where as long as you and your land meet eligibility requirements you will automatically be accepted during signup periods. So if you want to sign up for one of these CRP programs and we are during a signup period and you meet requirements, you WILL be accepted.
There really are a lot more options out there for agricultural landowners then most realize, and they are designed with both farm production and wildlife in mind.
CRP is much lower paying than the potential from actual harvest if you farm it. Even renting the land is still way more profitable. The only land that anyone usually wants in CRP anymore is something that needs tiled or has other issues.
The CRP programs have been slashed compared to years past and you more than likely will not be accepted.