Publishing isn't about getting into print, it's about finding readers. So the problem with something like Lulu is that it won't find you a readership. And given that it's much more convenient to put together a PDF yourself and link to it from a website, it's not clear what the service is adding if you don't already have a market for your book.

Getting into hardcopy certainly won't find you a market. Nor will it legitimise your ideas or give them authority or impact.

I think authors secretly suspect that's what hardcopy gives them, even if they're not necessarily aware of it consciously. And the vanity publishers - and Lulu isn't one, in the usual sense - deliberately capitalise on this with huge puddles of oily flattery.

In fact what mainstream publishing gives you is limited access to that legitimisation, and - more importantly - much wider access to potential readers through established marketing and distribution machines.

Some self-publishers do manage to create their own marketing and PR machines, but it's a ton of work, not cheap, and only sporadically effective.