Having worked at some of those companies, along with small startups, the biggest difference isn't really plain old sophistication, but expenses so high as to ma

Having worked at some of those companies, along with small startups, the biggest difference isn't really plain old sophistication, but expenses so high as to make the engineering effort worthwhile. If your production system is 10 instances on some random cloud, a 10% efficiency savings saves me 1 instance, so maybe $2k a year. Taking into account opportunity costs vs doing things that raise revenue, said startup would consider the effort a waste of time unless it took a few hours. With the same architecture, but instead 20K instances, then suddenly that 10% is saving 2000 instances, and 4 million a year. Unless there's a major engineering shortage, chances are that spending a over a month on 4 million in yearly savings will be completely justified, and would even be a highlight in someone SRE's review. Chances are that the optimization wasn't even any harder in the big tech company: It's just that small savings on big piles of money are suddenly worth it. It's not possible to find millions of dollars in loose change between the proverbial couch cushions if you didn't have the chance to spend hundreds of millions in the first place. Heck, in a growth company, even at that size, 4 million might not be enough savings, as there might be even bigger things. Same with dev tooling: Saving a company 5% CI times is not great with 10 developers, but if you are making five thousand developers more productive, suddenly you can hire an entire team of very specialized developers, and it's not a luxury. This is also why often copying what large companies is foolish when you are small: The tradeoffs are going to be completely different. What would be an unacceptable flaw in a large company is just fine in your startup. The real trick IMO is the 200-800 range: Large enough that the simple solutions for small companies have probably broken down and are causing pain, but nowhere near the staffing to hire yourself a team to, say, add types to Ruby, get a team to build around the weaknesses of your database, or whichever other problem you have that any member of FAANG would just throw 10 million dollars in staffing costs without batting an eye. I've seen way too many companies that stopped being able to grow their company at those intermediate sizes, and get stuck in technical hell.