More Closed Rhinoplasty Successes Attributable to Doctor's Experience?

Yes, it is true that surgeons who perform closed rhinoplasty often have more experience than those who don't. This is an older technique and is more difficult to teach to new surgeons during their training. For this reason, at many teaching institutions, residents are taught the "open" technique, where the resident can actually see what is being done by the senior surgeon. As a result, many younger plastic surgeons have never learned the "closed" technique, or simply feel more comfortable with the open approach.
This does not mean that open rhinoplasty is not a good option for you. A surgeon with experience in both techniques may be better able to advise you and achieve your goals. I would certainly look at the surgeons results and reputation before making a final decision. You definitely want to find someone with a lot of experience and who you feel comfortable with, before you go ahead with surgery.

I would not choose your surgeon on the basis of if they do closed or open. Each technique has it advantages and disadvantages. The technique chosen should be based on your anatomy and what needs to be addressed.
There are some things that open rhinoplasty is better for, and it does not matter how much experience the surgeon has doing the closed.
You just need to choose your surgeon carefully but not solely based on the if they do open or closed.