So many things in your house that are probably pissing you off:
it's very easy to replace an outlet that doesn't hold a plug or is a little off for whatever reason.
ditto light switches
door handles and shit. We hated the jank handle on our patio door that barely worked and required specialized training to get to lock. $12 for a new one, that was much more aesthetically from this decade. (that said, some lock lube, which is a thing, goes a long way)
ditto for the various shitty faucets in this house (or any slightly older house.) You can get a ton of bathroom fixtures for under $30.
hinges. Unless you're trying to re-hang a safe door, you're going to be under $20.
faucet diffuser. They just screw on. Have you lived in your place for more than a few years and haven't replace them? Just do it, it's like $4 a faucet.
doorbell. Smart doorbells can easily be had for under $50. A little easier often than replacing the traditional bell because you usually have a plug in chime rather than something wired.
a can of sprayfoam. Seal that area that is letting in air. Trim it with a box knife, chances are you won't know the hack exists.
I mean, the electrical stuff makes some bit of sense; you can seriously cause damage if you don't at least know somewhat what you're doing. I don't get the plumbing thing, though.
It's rare to hear of someone killing or injuring themselves working on home electrical fixes. I'm pretty old and can't even recall an incident. Most people won't do it because they do have enough fear not to play around with it. But if you do know enough, you know how incredibly simple it is to replace an outlet or light switch and how to do it safely. Even a overhead light or fan is pretty trivial. Also the US 120v standard is less likely to cause harm with a stupid mistake than some other countries that have higher voltages. I'm thankful the states allow homeowners to do this themselves.
There are definitely things people shouldn't do with a license, but swapping switches and outlets is more trivial than changing the oil on your car.
Swapping switches and outlets is more trivial than changing the oil on your car if you turn off the breaker first.
And to be clear, I'm not saying that the US should adopt laws like Australia. I'm saying that I understand why Australia adopted those laws.
I do know how to do the basics. I've installed smart switches and outlets, doorbell cameras, ceiling lights...I haven't had cause to do an overhead fan, but I'm pretty confident I could manage it.
I'm glad I have the ability and legal right to do so. But electrical fires destroy 51,000 homes a year, and most of those are caused by faulty or poorly-installed components or wiring; and that in particular can affect not only you, but people who live with you and even neighbors as well. And the U.S. CPSC estimates 400 non-professionals die of electrocution every year.
Add to that that, as you say,
Most people won't do it because they do have enough fear not to play around with it
...but those who don't are split among the people who know what they're doing and the people who are too stupid to see the risk. Is the danger caused by the idiots worth banning it for everyone? I don't think so, but I understand and respect that decision for Australia.
Indeed. I've DIY'd all of that and then some, and especially in the age of YouTube in which you can find a hundred videos from electricians that have been around as long the light bulb, it's some of the simplest home repair/upgrade you can do. And although you do need to respect the inherent danger of working on currents like this, electrical is actually pretty easy to understand for the types of home upgrade/repair like this you might attempt.
Just be mindful of what you can and cannot do based on local regulations. You definitely don't want to have your house burn down and your home insurance tell you to kick rocks because there was a code violation somewhere, even if it didn't cause the fire.
Pro-tip for the spray foam - if blocking air from the outside, spray a little bit of foam, add a "wall" of steel wool, then spray more foam on that. Stops the mice chewing through it