Logan Shaw wrote in
:

To put it a slightly different way, for that $30 DVD player, it
costs something like $10 labor and $10 materials to put that
thing together in the first place (because there are packaging
and shipping costs and profit). So how efficient is it to spend
$30 labor fixing it? It isn't efficient. Repairing
mass-produced items isn't efficient because one person working
on one item and doing everything by hand simply doesn't have the
same economies of scale that a highly-optimized manufacturing
environment has.

- Logan


To give a better example, look at the HP higher-end credit card sized
calculators like the HP-35 and -45. They are designed to not be
repairable. All they are are a circuit card, a keypad and a display.
They did the analysis, and it was cheaper to design the unit with an
assemble-only push-together design and handle warrenty work by just
replacing the unit, then designing it with screws so that the failed
part could be replaced. Needless to say, they also went through the
entire product and tightened up on everything they could so that they
could cut down on the incidence of repair at the same time.