Yes, it is well known there are a certain number of mutations (indels, point mutations, chromosomal rearrangements, etc) per division and cells in a dish divide

Yes, it is well known there are a certain number of mutations (indels, point mutations, chromosomal rearrangements, etc) per division and cells in a dish divide many, many times. Why would anyone think they would not harbour significant levels of genetic variation? This makes it sound like they just spent 40 years misinterpreting data because they didnt do some basic algebra.