I have a PhD in English and history and I had no clue how it was pronounced.
And here's the thing: contrary to popular belief on Mumsnet, academics in the arts and humanities do not tend to equate knowledge and learnedness with running around correcting other people's pronunciation or grammar. Nor do they see that kind of thing as the be-and-end-all of scholarship. People tend to be more interested ideas and the ways that they are expressed. I've seen very, very brilliant people misspell words. Who cares?
It's the equivalent of complaining that a biologist who can teach your kids about cells in a brilliant way but pronounces 'cytokinesis' idiosyncratically. Does it really matter? The main thing is whether the teacher can break down the play and bring it to life for your children, leading them through it so that they can understand the basic ways in which it works. The mispronunciation of 'Glamis' doesn't affect their ability to do that.
In relation to a PP: yes, it's quite possible to get an English degree without reading Macbeth. The number of works that can be crammed into 3 years of study really isn't huge and most people take considerably longer to master a particular era (even an early one, where it is actually possible to read most of the stuff coming off the press - as soon as you get beyond the mid C18 it becomes pretty impossible to read everything published across a relatively short 50-year period. I've been working in my field for years and there are still absolutely tons of things I haven't read).
There's also a bit of an irony in being pernickity around Shakespearean language, given that the reason he stands at the pinnacle of the canon is his tendency to tear up the rulebook of language and to invent all kinds of creative new ways of using it. If there had been a Mumsnet or a grammar police back in his day, his plays would have spawned AIBU threads galore: 'Hamlet: AIBU to think that 'barefaced' is NOT a word'/'AIBU: what, exactly, is a 'wrangling pedant', Willy?'/ 'AIBU: is it just me or is Shakespeare just wrong in the way he transforms nouns into verbs?' 