Why don't they make 4 wire Romex (plus ground).
There are many 2 or 3 way switch circuits that need 4 wires plus the
ground. 3 wire is all they sell. I can think of other cases where I
could use 4 wires too. For example, I had to run two common strands
of romex to a double light switch that also feeds an outlet. Two
switched wires, one hot, one neutral. That's 4 wires. So now I have
an illegal white wire controlling a light from a switch. Why not 4
wire romex with black, red, blue, and white. (patriotic too).