These user activated dictionaries tend to be excellent (even in vim, a pretty barebones system, I tend to get fantastic guesses from the machine).

Actually, come to think of it, the problem must be a bit easier than on smartphones, right? Real keyboard input is very precise. Smartphone keyboards already guess what word you were trying to spell, so they are influencing the typos in the direction of likely words… cannibalizing the very guess list that the dictionary uses!