> then hundreds of dollars to service when they break
Can you explain what do you mean by that? It is quite rare to see broken trrs jack on a laptop, at least I have never experienced one, nor on walkman or anything getting heavy plug/unplug use.
I thought it is an issue in reducing the cost to manufacture the case or something.
All physical receptacles break and increase failures by measurable amounts at mass-production scale.
You take care of your hardware, even during "heavy use," many people absolutely do not - and are downright abusive.
Many of these parts exhibit partial or intermittent failure modes where it's more expensive and difficult to determine warranty eligibility than to just fix the problem. Peanut butter in the jack, loose solder joints, whatever.
I’ve never had one break due to heavy use, but broke one on my work desktop due to forgetting I was wearing headphones and yanking on it when I got up.
Does anyone even do repairs anymore? Swap a motherboard and that's it.
The jack actually broke on my old xps. Changing it with an aliexpress replacement took about 15 minutes and something like 3€
So yeah, they break, but they are (or used to be?) quite cheap to fix (and this was one of the super thin 13" xps)