And why go down that road if they don't have to, there's
nothing wrong with asking for contributions in order to
put out a product they're proud of
As I said in my comment I would love to see a comment from someone involved with reddit previously or presently on whether or not the fear of user outrage is a driving force behind this refusal to invest in proper advertising, because it seems to be that way.
From the way the blog post reads I don't think the issue is that they can't make money with adverts, it states:
we can start running a bunch more ads
I think that if they want to really commit to the idea that reddit gold can support the site they need to have targets (A counter of the # of people that need to sign up this month), something that people can understand and associate with. If there's 50,000 people needed every month to be paying and it's at 40,000 people will be compelled to sign up to feel like they're contributing.