I think I generally agree with this, but that the bigger data point in any "build vs buy" debate is around the expertise/time available on the team vs the scale of the project.

For example, I worked at a 30ish person startup that was a little less than half engineers. Our product had a ton of traffic, and our growth/sales teams had outgrown the small bundle of cheap/free marketing tools we'd cobbled together. But marketing automation is expensive—so a couple engineers spent time trying to build our own version, insisting it was doable and that it would fit our use cases much better because it was built for them.

The reality is they spent two months working on a marketing automation solution that kind of worked, but was missing the robustness of a normal product that had been built by a dedicated team of engineers over years. The other issue was that those engineers now owned their solution—bugs, feature requests, etc. they were essentially running a second product now.

Eventually, for the sake of their time and our productivity, we just bought software. We could have done it months earlier and saved everyone time and frustration.

I realize this post is specifically about dev tools, but I think the logic is more or less transferrable.