But what really goes wrong with 'high tech' kit?
Let me say at the outset that my main use of a bike is as a means of transport. I have a reasonably serious commute (which I enjoy), and I occasionally do a 100k+ ride, and I wear lycra, but mostly it's about getting to work cheaply and without the costs associated with a car for me.
So with that in mind, when I bought a secondhand road bike with Di2 gears and they didn't work, I spent a couple of days trying to diagnose the problem using various versions of Shimano's diagnostic software before admitting defeat and giving the thing to a bike shop to sort out. After a new battery (and a £250 bill), I was on the road. Bear in mind that I could have sorted out any issues with a mechanical groupset in about half an hour, for the cost of a couple of quid on cables. Ultimately, the electronic gears (admittedly an older version from 2016) did nothing my mechanical gears don't do, but came with a significant serviceability penalty.
Likewise disc brakes: I tried them, found that I only had to think about lubricating the chain for them to start squealing like a dying pig for (when all's said and done) no great advantage over rim brakes, given the fact that the only way to stop the things squealing seemed to be to spend a fortune on new pads to replace the barely-worn pads I'd already spent a fortune on.
I think the main point I'm trying to make is that I've never found rim brakes to be inadequate in any scenario through 40 years of regular riding. Granted, it helps that I'm comfortable replacing worn out rims every few years, but I do think that for the cyclist who simply requires a cheap and cheerful means of transport, with absolutely no importance attached to the performance gains that come with discs or electronic gears or whatever innovations are aimed mainly at the racing cyclist, older and cheaper tech is very much the way forward.