to think that all (ok most) items of clothing should include a piece of material to patch one or two holes?

[BuzzLiteYear]

ie attached to the waist perhaps, 2 or 3 square inches would do.
This would make repairing so much easier.
Obviously clothing manufacturers may not do this voluntarily as turkeys don't vote for Xmas... but the times they are a changing and electrical goods manufacturers are being forced to make white goods easier to repair, at least in the EU (sigh!).

Yes, that sounds an excellent idea. I like it when jumpers come with a metre of the wool they’re made of so you can stitch up a hole or whatever without doing so in a non-matching thread.

A lot of higher-end outdoor gear dies, but I guess that is more to do with the expense and the difficulty of sourcing small pieces of Goretex or something!

Caving suits do, but that's because you glue the patch on, you don't need to be able to sew.

What proportion of people do you think have the sewing skills to sew on a patch?

whatever the percentage is, it will grow rapidly if this climate emergency is real.

Brilliant idea. A much-loved dress has been violently attacked by fucking moths, and I am struggling to find a way to discreetly repair it but I am GOING TO FIND A WAY if it kills me. Sadly not much hem allowance so can't easily steal from there.

What proportion of people do you think have the sewing skills to sew on a patch?

Well I run mending tables where I teach people how to do basic mending - I love it!!

What a great idea!

I tend to find that clothes wear at points like the cuffs or inner leg seams that would be difficult to patch.

I've noticed the DC's clothes often don't have spare buttons though. I have to nick the top button to replace a missing lower one. Annoying.