Pretty much all lies from the start.
First off, almost nobody is missing steps in their cheap 3D printers. They simply do not move fast enough for that to happen. And if they are missing steps you have a bigger issue, usually lots of friction somewhere.
Secondly, 200 steps per rotation is normal for motors. However, the drivers everyone is using do 16x microstepping, good for 3200 steps per revolution. Accurate steps per revolution. That's better then 4096 +- 2 steps.
You also lose the close coupling between the 4 axis that you need (the feed stock of the material is also an axis that you need to control), which is a big deal in running accurate prints.
The cheap hobby servos will also have mechanical play, which will cause vibrations to be transferred to the head, which will result in a reduction of print quality.
I'm also willing to argue that it's more expensive. But I didn't do the math on that part yet.
(Who am I to say so? Just a guy who has been working at Ultimaker for 2 years. Kinda know what's needed for quality 3D printing at a low price and what's not)