b12 deficiency may not happen for years, (because you need only around 2 micrograms per day) and even some of the most passionate experts have had problems with b12 deficiency (including Douglas Graham). Some vegetarians eat milk and eggs, which contain b12, or some others get supplements.
This guy is total raw vegan, has a site called 30 bananas a day. Takes b-complex shots.
While you discard scientific research as "hypothesis", if you are relying on anecdotal evidence, that shows me the level of your research, and scientific thinking skills.
And while you know nothing about my health, even if assuming they were healthier than I, it would be irrelevant to the issue at hand. I may be less healthy, but right about b12. Health is not a single-factor thing. I may have enough b-12 but have a host of other problems.
Here is more info about b12 deficiency:
http://europepmc.org/abstract/med/12643357