For the life of me I could not find the logical argument for
the truth which I felt inside, that inhouse development is the light...

Quote from Carly Fiorina - (CEO of HP)

That says it all right there. I would suggest the following;

All business that does not push back the boundaries, that merely
tries to make do with pre-fab parts is doomed to follow the leaders that
go the step beyond to create something new.

This is not to say that the wheel must be re-invented. But it does suggest
that there is a point where re-use becomes shooting yourself in the foot.

-Ivan