As an avid reader for (consults a calculator) 66 years, I can tell you that yes, the frequency of typos has indeed increased. Greatly.

I recently read a book that had been re-released by the author because he was angry with what editors had previously done to his story, as he explained in a long preface. Well, that book read like it had been written for an 8th grade writing class. Authors should not edit their own work for the same reasons programmers don't do QA for their own code.