Reading every word of a PhD thesis is ridiculous. The point of the thesis is that it forces the student to survey the entire range of the literature and place their own scientific work in a much broader context than is possible with a peer-reviewed publication. If the student did good publishable work in the lab, it doesn’t matter if there are “that/which” errors in the thesis. Who gives a fucke? This isn’t like in the humanities, where a PhD thesis frequently becomes a published book.
What matters is the underlying science and the breadth and depth of knowledge of the student about her field. The former can be assessed looking at the figures, and the latter during the oral examination. The purpose of the thesis is the process of writing it, not the final product.
And BTW, the other thing I don’t understand is this cockamamie notion that it is important not to allow someone who doesn’t “deserve” a PhD to get one. If the poor fucke spent five or more years in the lab, and they at least tried at some level to be successful, then if they write a passable thesis, they should get their fucken PhD. It’s not like giving someone an accounting degree who doesn’t know shitte-for-dicke about accounting and could fucke their clients’ shitte uppe, or a doctor who could kille a motherfucker.
What harm is some poor fucke who didn’t “deserve” a PhD gonna do with it?? Try to get a seat at a hot restaurant by making the reservation under Doctor Undeserving??