Interestingly, I have had the opposite experience. In a legit startup, at least one that is pre-significant revenue, when you are still looking for "market fit"

Interestingly, I have had the opposite experience. In a legit startup, at least one that is pre-significant revenue, when you are still looking for "market fit" (aka bleeding money), you don't have the time to reinvent the wheel. Its more like "Please god let there be some reasonably workable library already built for this so I can focus on the important stuff!" Bigger companies IME, tend to be the ones that can afford to reinvent the wheel, and also tend to have the ~~arrogance~~ size to feel that they are a special enough snowflake to eschew something off the shelf and build something custom tailored exactly to their needs. They also have big enough budgets to be able to spare the manpower on it. My experience has been largely in the financial space, maybe that is the key difference.