I've seen plenty of websites flourish with a well laid out affiliate program.

Some people don't want to post because they aren't confident with their writing skills. I myself think I'm an OK writer, but I do know a lot of super affiliates who would rather sit in the background and grow a website. Some of these people have been to only reason some websites make any money.

Not having an affiliate system will reduce the amount of exposure you can obtain. Sure a website can get big over time, but if you want to be the best, you will need people helping.