"Don't reinvent the wheel" is so often little more than a lame excuse spewed by the lazy, ignorant, or just plain stupid. The sad part of that being that in the long term said mentality always seems to lead to more work, more cost, and the increasing probability of failure.
I've seen it time and time again, which is why it's in the title of my own article on the topic of web developer excuses:
As I say in that article, what if people said that to Dunlop and Michelin? Cars driving around on steel hoops heat-shrunk onto wooden rims?
There's what I call the "credit mentality" behind how people choose bad off-the-shelf answers. Pay more later for something you can't afford now. That's the entirety of it and it is no plan for success.
Code debt is real, and bad choices with off the rack answers at the start can utterly bone you down the road. As Patton would say, an ounce of sweat now can save a pint of blood later.
But right now EVERYTHING in society is built on the credit mentality.