Busse Combat MOAB is 0.41" thick of INFI steel. I honestly doubt a person could break one short of putting the end of the tip in a vice and using a very long cheater bar on the handle with a couple of guys bouncing up and down (full weight) on it.
I'm a dedicated fan of Busse Combat, Swamp Rat, and Scrap Yard knives as I've been a user / abuser for the past 11 years and have yet to break, chip, roll or otherwise damage one (the finish will get beat off of them).
As far as blade thickness goes ...
Quality steel and proper heat treat is more important. I'd take a 3/16" Busse Family product over a 5/16" ESEE, Becker, Gerber, Buck, Fallkniven, etc.
I've owned many: Buck, ESEE, Gerber, Grayman, Fallkniven, Bark River, Ontario, Browning, Cold Steel, Becker (both fabricators), and so forth.
Busse / Swamp Rat / Scrap Yard are the bomb.