Inexpensive kitchen knives tend to be brittle because of the way they are ground (thin) and the way they are tempered. Keeping them harder gives better edge holding ability, but they are at higher risk of breakage from sudden impacts or torquing/twisting.

Inexpensive outdoors knives seem to be tempered back to give reasonable toughness (at the expense of edge holding ability). For folders at least, the handles tend to break before the blades do -- or at least they used to, since I haven't had a catastrophic failure in a long time.

Note that manufacturers of inexpensive knives often cheat a little, burning the temper on the edge during final sharpening. It's a thin little layer that stays sharp longer, but it's the devil to sharpen after because it also creates a tough layer right underneath. Once you chew through that, and it takes work, you're into the regular steel of the rest of the blade.

I have burned up a lot of inexpensive ($10) knives over the years. They take the unreasonable **** and abuse of rough work, saving my good knives and Leathermans from unnecessary wear and tear.