My wife has Crohn's and has NO symptoms while on the SCD. If she cheats just a little - boom - the pain and other symptoms come right back, but go away again as long as she sticks to the diet. For us, that experience is proof enough that the diet works, because she still does have Crohn's, but has no symptoms on the SCD. I Wish I could give you more solid proof, but hundreds of success stories like these merit consideration. The diet is inconvenient for sure, but I'd trade that any day for a dreaded disease like Crohn's! My suggestion is to go to the SCD websites like www.nomorecrohns.com for recipes, starter menus etc... THERE IS HOPE!
As to why the SCD has not been studied much, well, the drug companies are the ones with the money to fund the studies, and it is not in their financial interest to pursue dietary "cures". (Not that the SCD is a cure). Doctors are reluctant to recommend dietary approaches for fear of malpractice... So in the end, you have to decide to take your own health into your own hands. Nobody cares more about your health than you do, because nobody else has to live in your body.