Disposable razors need to be made with wider spacing between the blades so that hairs don't get stuck between the blades.  Right now the lifetime of a disposable razor is determined by the amount of time it takes for the spaces between the blades to get irreversably clogged up with hairs (less than one complete shave), rather than the amount of time it takes to dull the blades.   Also, they seem to deliberately design the plastic part of the razor to deflect attempts at running water directly backwards through the blades, in order to prevent you from unclogging them.

Because of these annoyances, I just use an old fashioned single-bladed safety razor, which can be easily cleaned and unclogged.   The blades come in packages of 200 for like $20.