Originally Posted by
icepick_trotsky
A freewheel can only get as low as 14t, sometimes 13 depending on the model. A cassette, by virtue of its design, can go as low as 10t, so they do.
Thus the invention of the compact crankset, because most of us will never use a 53x11 combination.
I remember when the standard freewheel for racers was a 13-21 6 speed. I even ran a Regina Oro 12-17 for a while, which was a little silly. Anyhow, BITD you certainly could get freewheels with 12 or 13 small cogs, though a 14t was the usual small cog for an average cycling enthusiast.
Back to the OP: I suspect the current availability of cassettes is driven by a need to be able to sell the same thing to MTB and road bike people. Pretty much all MTB cranks are 'compact' as are many (most?) road bike cranks these days.