You can make anonymous accounts, but there's a difference between 'breadguy' and 'anon'. Who is literally everyone posting on the board. In the chan world so called namefags are shunned and not thought of as true channers. By having an identifiable name it gives you some measure of reputation, a name that you may hold some regard for, or at least that others could decide if they want to listen to or block.

I actually like to think of the chan boards as an experiment in social studies. What happens when you allow for purely repression and repercussion free interaction? There are plenty of people who will say and do some absurd things when they're drunk that they wouldn't dare to sober. What happens when that sense of untouchability is available at any time just by going to a website.