I guess a lot of things aren't that simple or accessible as most of it is often a black box nowadays. But anyway, Skills like these not only saved money but also fostered a sense of self-reliance, resourcefulness and stuff your parents taught you as life skills.
[1] Or a pre-requisite. Correlation, not causation and all.
The “quality” part is a big factor, cost optimisations and fast turnaround means it’s often not worth repairing things at all e.g. a fast fashion T designed to survive for a season (if it survives even a wash).
An other major issue is scams around price signals and brand degradation. It used to be you got what you paid for and some brands were known for quality, so you could pay a fair amount of money to a reputable brand and you’d get stuff worth maintaining and repairing.
But big groups and P-E have taken to “value extract” from brands, so they take a reputable brand and start white-labelling / cost-optimising, initially keeping prices in order to get maximum money for the moo their start selling instead of milk. Then they drop the price as understanding slowly spreads, until a once reputable brand becomes bargain-bin fare even to the general public.
There’s a similar issue around more bespoke products, which optimise for quality signals (e.g. external design and materials) and sell generic inner parts (or outright garbage) for top-shelf prices.
Then there’s the shuffling of 6 months brands on generic white label goods (amazon is absolutely infested with that, you’ll get the exact same product under half a dozen brands, and 6 months later most of those have disappeared).
Cars are worth fixing, a 10$ shirt is not, if you value your time. This only becomes more true as expertise becomes required to effect a repair, since you become less capable of repairing and the time of the repairer becomes more valuable.
I've been doing maintenance on my motorcycle myself recently, it does take some small investments in some tools to get started (like a tool to undo the oil filter, although in hindsight a strap and a stick would do the job) and you need to source some parts and replacements (fluids, copper washers, but also replacement screws for the weathered brake fluid reservoir ones), but it's in the region of €100-€150 instead of the €1000 the garage quoted me for.