no moving parts

Mechanical bells in phones were nice. If you slammed the phone on the receiver you would get a nice ring from them.

People also didn’t own the phones themselves. They were usually rented from the phone company as part of the service contract. So the phone companies had an incentive to buy sturdy equipment. Consumers buying things for themselves often buy the cheapest they can, resulting in lower quality. Yes, lots of products today are worse than they could be, consumer demand for cheap devices plays a role here as well.

microwave ovens

There are only a handful of companies making the core component magnetrons. Various brands just package it differently.

My Bosch vacuum cleaner is 11 years old and works great. The only problem it has is weaker cable retraction. My Bosch washing machine is 7 years old and works fine. My Samsung fridge is 5 years old and great. My Miele dishwasher is at least 15 years old and works great. My no name brand cheap toaster is 17 years old and works great. So from personal experience, I think this is acceptable.

Landline phones were mostly plastic and took lots of abuse for years just fine.