My experience is that I can only make 1 pound of steel chips per hour
with my mill with end mills bits.

But drilling on centers in my lathe, about the same size, I can make
chips 3 or 4 times faster.

My theory is that the drill is balanced. That allows more tool force
with less stress on the tool and kept the vibration from being the limit
of cutting rate.
A single flute drill would be as slow as the mill, as I can tell from
how slow a boring bar works.

I don't even use the shaper.