If you have a more serious issue the default procedure is to just wipe the device and replace the logic board for the flat rate repair fee. I have a macbook that just shuts off randomly and turns on with CPU1 halt error messages. I bring it to the apple store and they told me flat out they don't know what is going on with the device, gotta replace. Also had macbooks with gpu issues, same deal send away wipe the device and replace the logic board and hope that fixes it. I had a macbook where the flex cable to the screen was going and same thing, wipe and send away. All they do in the store is software based solutions, they scan for hardware issues and they send it away to be repaired.

I wonder what sort of issues you had that could have been fixed in 30 minutes or what sort of replacements you've been given? That's not been my experience at all at apple stores and I've been bringing them screwed up laptops to fix for ten years. I've never been just handed a replacement laptop that day, its always been send away the computer for at least a week and they try gutting it and putting in all new parts vs troubleshooting the underlying issue and replacing the perhaps one bad component that is the root cause.