Rii-iight. There is definitely room for writing bespoke software that just does exactly what you need in exactly the way you want, but the problem is that there’s generally a tendency for “what you need” to expand over time and you find yourself spending not 1-2 days but 1-2 months of each year writing code that someone else has already written.

You don’t choose FOSS because you like abstractions and general solutions but because, well, it is free. And you remain independent. And you can actually verify yourself that the software is well-built and worthwhile to build on.