I am fine with attributing others. I have actually done it after paying even when paying removes the need (e.g. glyphicons pro).
it's greed, ego, etc.
Greed is actually a very poor reason for not sharing back. It actually costs more money to maintain a forked code base than contributing the change back and getting it maintained by everyone. It is also fairly stupid to hide what software you are using from a recruitment point of view.
I prefer the BSD / MIT licenses because the sharing occurs on my schedule, less stress, and less friction. I like doing things because it is right and not because I have a lawyer at my door.
And I don't think its greed. Not many applications on any platform gets written completely from scratch without using other libraries.
Most permissive licenses need attribution (in form of leaving the
original header comment etc) which lets the whole world know
If the code is being used for commercial and propriety purposes then the code is never seen, never attributed. Attribution in the form of source code comments is really only valuable in other open source projects.But then practically all my own current work is open-sourced which probably skews my opinions.