In your initial post you put three things up: the great vowel shift, printing, which more or less coïndided with that shift and etymologizing which tends to support conservativeness in spelling.

Vowel shift. They happened all the time through history. Gradually and at times explosively.
The dawn of printing. Do you mean that the introduction of printing made people more aware of language, grammar, phonology, syntax ? Was there clear a connection ?
The etymologizing of... 'The tendency to preserve etymological features even after phones have changed drastically' means pronunciation and written word did not develop completely synchronic ? And in remote parts of a language region did and do not some old pronunciations stay on, just because they were less touched by the sweep of time?
Dialects preserve old sounds.

Do you think internet and the worldwide hyperactive migration of people causes a sort of explosive vowel shift? I know there is a far greater difference in grammar and sound between me and youngsters today then there was between me and my grandparents.

Any comparison between the introduction of printing and the internet?