> I strongly believe that you cannot evaluate how good a system design is if you don't implement it by hand.

Fwiw we both agree that LLMs should not design systems. I do the design, but otherwise I don't get how this is true, the success of a design is indicated by long term success in the system it built. You can measure this against success in the task it was deployed for via performance metrics for one. And then from a developer standpoint how easy it was to maintain later on. Success of a system is a measurement over time, but it's not some quality that can only be measured by those who built it.

> Off-topic but having worked in other companies as well, I can guarantee you that this is not the case. The skill of engineers in FAANGs and other "top tier" companies is much higher than average.

I have first hand knowledge of this so I agree to disagree. Being surrounded by google, aws, and meta folks my understanding is the best people leave faang when they get the itch to do something better with their time.