The difference is that in all of those instances you have a more immediate ROI vs. internal training. If you roll for a week straight with someone who is good, you should be demonstrably better at the end of that week. Internal training requires a reconditioning and retraining of the body that is tiring, both mentally and physically and to be perfectly honest, BORING at the onset. That's a hard thing for a lot of people to do, especially when even after that initial hump, it's still not something that you can really "use" in the same sense as you could other more direct training. It's just the initial hump that you need to get over in order to really be able to feel what you're doing, what your uke/partner is doing and work toward building the connections and such that are needed to eventually get to normal application and it doesn't get any easier.

To address the other aspects of your post. I do NOT do this stuff because I feel there is anything ineffective or wrong with my aikido or the aikido as taught by our small organization. I have been in fights with my aikido and successfully used it to defend myself. Not matches or sport, but fights where I knew there were no rules to protect me so I damned well better protect myself. I am not alone in that within our organization either. I don't say that to portray myself as some sort of badass. I know good and well there are untold numbers of people who could kick my ass, but the notion that all aikido is weak and "doesn't work" and that everyone who practices it is being sold some snake oil is and always will be laughable to me. Good technical aikido, hard training and honest training (if you don't move, you WILL get hit) can still provide you with a good and effective set of self defense tools. I know this is not the reality of most aikido, but I knew that twenty years ago too. I was here back in 2000 saying many of the same things Tony says today, albeit (hopefully) without the insulting tone. Had I continued to hang around here I would have very likely been one of the people calling Mike and Dan idiots as I relayed the above story. Fortunately for me I was not, but when I returned and started reading their posts, I wanted too, but the curious nature of age is that it changes us. So rather than do that I continued to read and I found myself getting more and more interested. I eventually found some local people who were working on this stuff and actually had some demonstrable skill. I went in as a skeptic, but with an open mind. We still come from a ki society background and I honestly believed that I did "relaxed" pretty darned well. I was wrong and I immediately knew that what they were doing was very different, in body, than what I had done and I wanted it. Not because I felt that what I was doing was weak, but because I honestly felt that it was the path to something "more" than what I was doing. As I've developed what tiny skill I have I find so many connections to the things Ueshiba used to say that were written off as "spritual gibberish" and I love that. I find it fascinating that the human body can do some of this stuff. I can hardly do anything these days without mentally taking stock of what's happening within my body and then making adjustments to try and get some measure of IP training out of it or see if using my body that way, the correct way, yields a different result.

Anyway, I got off on a ramble there, but the point is that I made myself one of the "chosen few" and anyone who is interested can do the same with just a little effort. People who are unhappy with their aikido, feel cheated by it or whatever and are waiting to have something proven to them before making efforts to fix it, probably don't have the mindset to do it in the first place. They could have done plenty to fix their aikido before Mike and Dan showed up and they didn't, so their disappointment and trust issues are largely their own.