I think the whole “diversify your anchor text” notion is a myth, based purely on Cargo Cult Science.
I have found no evidence to support this notion in all the data I have analyzed, nor have I heard of any credible evidence made available to the public. Repeating false information, over and over again, may cause people to start to believe in it, however, that does not make it true, it just makes it into misinformation.
I am open to taking a fresh look at this notion, if anyone has any credible evidence to share, if so, please do.