It depends on the sort of journeys you are doing. A spares kit for foreign travel makes perfect sense to me, particularly containing hard to source, known to fail, and easily fitted, smaller items.
By your argument, we would not have carried a spares pack on Tristars, the majority of which was never used, however ONCE I was able to save the company significant sums by fitting a starter motor from the pack, thus preventing an unnecessary night stop for 300 odd pax with all the associated costs, including a wrongly positioned A/C for the following day. A different case I agree, but spares carried on the same principle.
Where one draws the line is a subjective decision.
I take exception to being described as a moron, however your tone is in keeping with many of your patronising posts to those like myself who do not have your presumed high level of skill, which is a pity, as your experience demonstrates that you clearly have the ability to help people with their mechanical problems.