These are all legit concerns, and on paid projects you really don't want to reinvent the wheel as long as the existing wheels do the job. You'll save time/money

These are all legit concerns, and on paid projects you really don't want to reinvent the wheel as long as the existing wheels do the job. You'll save time/money, it will be easier to maintain and safer, and all those other pros mentioned are 100% true. However, problem with this popular approach is that it has become a sort of gospel preached to people, and they effectively brainwash junior devs in believing that they shouldn't ever dare to challenge the existing libs, and try to make their own improvements. Ever. And that is obviously very wrong. People shouldn't be scared to fork a project and make their own customized version that solves their particular problems better. That's what OSS is all about. Yes, most of it will suck, but that's how you learn. And some will make actual improvements so we will have better wheels in the end.