AFAIK Hinduism is the only major religion that incorporates reincarnation in its theology, and those who take reincarnation seriously most definitely believe that everyone undergoes it. Even the lower animals, since if you're really an asshole you might come back as a rat, a cockroach or a flatworm.
Considering that up until the closing decades of the 19th century, 99% (or more) of humans were farmers, it is indeed amusing that very few of the people who claim to have memories of a past life remember being farmers. Depending on the era, a considerable number were also slaves, and I haven't heard of anyone remembering that experience either.
This in itself casts doubt on the veracity of the claims: they are statistically unbelievable.
Oh yeah, and people who speak English usually remember past lives in which they spoke English. The English-speaking community was a whole lot smaller before the colonial era, so it's hard to imagine how all those anglophones fit on Britannia.