It seems you are taking his words a bit too literally.
He did (and still does) say that social anxiety cannot be overcome by a single method, and what he means by this is that, for example, I cannot overcome social anxiety completely by using only slow talk. Slow talk is a terrific cognitive strategy to use when you are anxious, but if you only use slow talk and no other strategies from the therapy, then you're probably not going to overcome social anxiety that way.
On the other hand, this doesn't mean that you have to become proficient at and implement every single strategy from the therapy every day to get over social anxiety. I say this because I certainly have not used every single strategy simultaneously, and I do not meet the criteria for being socially anxious anymore. I used several different strategies, yes; not just only one strategy, but I did not use every strategy from the therapy either.
The thing about these strategies is that only so much can be covered in a hour long audio recording, and Dr. Richards does go into more detail explaining the therapy and strategies in the local groups here at the Institute. But the series gives the general idea on how to utilize the strategies to your benefit to help you overcome social anxiety. If can keep moving forward and using some of these strategies, your brain will start to figure out what works and what doesn't. Not every single strategy works for everyone...I knew a guy from the group who said that the mingling strategy from one of the mingling handouts in the series worked wonders for him...meanwhile, I never looked at the aforementioned mingling handout a second time. Please keep in mind here that I'm not saying you can just pick and choose the strategies you like the best, but it is simply impossible to master every one of these strategies and recall them whenever you feel anxious. There are just too many to do that, so do your best to not pressure yourself to proficiently learn and implement every single strategy from the therapy.
Hopefully that makes sense, but if you have any other questions about this feel free to ask and I'll be happy to try and explain it better