Do the simplest thing that could possibly work

I think this works in simple domains. After working in big tech for a while, I am still shocked by the required complexity. Even the simplest business problem may take a year to solve, and constantly break due to the astounding number of edge cases and scale.

Anyone proclaiming simplicity just hasnt worked at scale. Even rewrites that have a decade old code base to be inspired from, often fail due to the sheer amount of things to consider.

A classic, Chesterton's Fence:

"There exists in such a case a certain institution or law; let us say, for the sake of simplicity, a fence or gate erected across a road. The more modern type of reformer goes gaily up to it and says, “I don’t see the use of this; let us clear it away.” To which the more intelligent type of reformer will do well to answer: “If you don’t see the use of it, I certainly won’t let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it.”"

I remember reviewing some code of an engineer I was managing at a FAANG. Noticed an edge case. Pointed out I thought if/when that hit, it was going to cause an alarm that would page on-call. He suggested it might be OK to ship because it was "about a one in a million chance of being hit". The service involved did 500,000 TPS. "So, just 30 times a minute, then?"

And you're right about the amount of engineering that goes into solving problems. One service adjacent to my patch was more than a decade old. Was on a low TPS but critical path for a key business problem. Had not been touched in years. Hadn't caused a single page in that decade, just trudged along, really solidly well engineered service. Somebody suggested we re-write it in a modern architecture and language (it was a kind of mini-monolith in a now unfashionable language). Engineering managers and principals all vetoed that, thank goodness - would have been 5+ years of pain for zero upside.