Distribution is still a major issue.
Cost of making a copy is ~$0 now, but it's still hard to distribute your information.
It's not hard to distribute your information. Wordpress.com, Youtube, etc. make this extremely easy.
It's hard to get people to care about what you have to say enough that they keep reading it, but making text available to people (well, people with internet access) who want to read it has been entirely solved for more than 10 years.
In a sense because of the increased competition (and increased content available) it's even harder.
Otoh, in theory the hard work has shifted and it is possible to get your info distributed in a "diy" fashion. For example you could write a blog, get a following, and sell a book. I'm sure if PG came out with a book there would be a market for it. Back in the day a PG would have to convince a publisher that there was a market for what he wanted to write. So it's really a shifting of the work needed to get distributed.
The hardest part of distribution seems to be advanced filtering of content and matching it with interested/relevant readers.
Whoever is doing that filtering/matching the best - is best suited for distribution.
Is that filtering/matching work best done by the publisher or the writer?
The writer should know her audience the best.
Who is in the better position to make such match: publisher or original writer?
One of major issues with publishing was distribution. Merely having the tools (back then) to create printed content was not the same as being able to put it in the hands of people that would want to read the content. Without the distribution (or the money to advertise) it didn't matter that you could run off copies or even if you owned your own printing press and bookbinding operation. You still had to get the product in the hands of the public.