My own attitude has always been, "why carry a 3" blade if I can carry a 4" blade?" So, 4 1/4" sounds good to me, too.

However, most knives pull up short by some fraction of an inch of that 4" mark, and many of those still have had handle designs which really made them a pain to wear.

That may be why the common length shorter than 4", but also suspect their larger markets may have legal impediments in longer blades, and no sense making a knife which most of the market cannot buy.

My old AFCK, really the first G10/titanium/wondersteel(ATS34 at the time)/liner-lock "custom quality" to hit the mass market, and really nothing but a Spyderco in design and even royalties, was just not very comfortable. Too long, too hard edged.

The Hinderer really somewhat an easier carry due to better shaping, despite weighing what must be about twice as much.

I learned some lessons from that AFCK in what to look for, to dodge such problems again in fair amounts blown on unworkable designs, and mostly successful. Mostly.