Repartee wrote:

I took it to mean that the type bars jammed into a bunch in midair, but now I'm thinking you meant that the carriage had not had time to move over a full space for the next letter...  I find that if I exceed the speed of type for certain common letter combinations the first is the usual result 

I think you'll find that it's actually about your technique and the condition of your typewriter rather than speed.

Speed typing competitions were all the rage during the first two decades of the previous century, and they irrefutably proved that the machines being manufactured back then, when used with the proper technique, were capable of speeds that far exceeded the capabilities the average typist. Champions made their typewriters sing at speeds that well exceeded 120 words per minute (ten key strokes per second) almost completely free of any errors. The typewriters were of course maintained to the highest standard of tune, but even so it illustrated that their mechanical design was sound, and that if an average typist experiences issues that they can be traced to either insufficient technique or a machine that requires maintenance. 
 

My car has a manual transmission, and even when tired and caught in stop and go traffic, I'm not really aware of my shifting as it's really second nature. I suspect it's the same thing for a true speed typist; much of what they do must be happening at a subconscious level.

As for electromechanical typewriters, I agree that they're more of a semi-automatic. I had a 1968 Karmann Ghia that had such a transmission; applying tension on the shift lever engaged an automatic clutch just before you shifted gears. Electronic typewriters are another matter and to my mind combine a computer with a printer, so a fully automatic with ABS brakes and traction control.