While this is quite correct, the 1 Hit per 3 Dice only simulates an "average" roll, meaning you have a chance of around 50% to get something around one third of your dice becoming hits.

There is always a very good chance, that you don't get this result.

Actually the 1 hit for 4 dice tradeoff is even better than you might think. For "paying" 4 dice you get a guaranteed hit. As there is no guarantee on a roll that you "allways" roll n successes by rolling d dice, there a times where the chance for such a roll rates above 90%, which is a very good chance.
I checked the probabilties and stumbled across the following:

The first time to make at least one hit with 90%+ is with six dice.
For at least 2 successes it is 11 Dice.
For at least 3 successes it is 15 Dice.
For at least 4 successes it is 18 Dice.
For at least 5 successes it is 22 Dice.
For at least 6 successes it is 26 Dice.

Whereas i can buy 1 for 4, 2 for 8, 3 for 12, 4 for 16, 5 for 20 and 6 for 24.

The 1:4 exchange is also an accurate tradeoff, and in the "low dice" department it is even better as in the "high dice" area.

While, of course, a 1:3 ratio will increase the hits one may buy, i personally stick with the 1:4 ratio, because it suits my understanding of game balance better.

You're negating the possibility of glitches when you take autohits. I view that fourth die (and the 1, 2, or 3 remainder dice) as the price of safety.