favourite pair of shoes has velcro issue

The little hooks become pulled out of shape after time, so can't catch on to the loops. You may only need the hook side replacing.
Super glue sounds a good idea.

I have some canvas Mary Jane type shoes which I use indoors instead of slippers and the velcro seems to have given up on them. I tried the self-adhesive velcro which seems to stick to fingers, the table, everywhere but it didn't stick well enough to the shoes.

It is annoying, I agree, when the shoes have plenty of wear left in them and I never thought of the cobblers, although ours is very expensive.

Mine are not clogged up, but I do know what you mean, I'm always picking the fluff out of the velcro on the DGD'S shoes!

The Velcro is probably clogged with fluff. Is it possible to comb or brush it through to clear it?

Worth trying a shoe repairers. Our local man in the market did DGD's school shoesfor a fiver which saved £40 on new ones before she had grown out of them.

You can buy velcro strip by the inch from haberdashery shops. That and a drop of superglue should work

Timpsons might replace it.