I agree you can't sell potatoes to potato farmers. The sites would be sold to end users. As the economy tanks more people will have to seek more niche income opportunities, mostly local i'd imagine and the most efficient way to promote and admin is via a website and these folks don't want to get involved in web building and SEO, rest comes down to pricing in my view.
I think you're assuming too much. At the moment you can divide it into three:
a) those who don't have any kind of website and/or sell via Facebook and eBay (i.e. people who don't want an ongoing cost such as web hosting and/or think they lack the knowledge to run a website).
b) those who pay for sites to be set up (mostly overseas if they're money-conscious, and almost always stemming from their own market/keyword research rather than having that determined for them).
c) those who build their own.
So you've got two areas to rule out immediately, and a possibility of b) but as I said, it's a case of actually finding people. Most money-conscious people will google how to create a website and then read lots of niche marketing forums and blogs. There's a small market on Flippa but most without any earnings at all tend to get ignored unless there's a very persuasive and well-marketed listing.
You keep talking about opening the market up, but without any practical ideas behind it. It's not just inevitable because of the economy; the economy has been shit for the average UKer for four years now. What you're saying is nothing new; people have been saying the market will open up for at least ten years and it still isn't happening. So let's hear your ideas on that instead.
Personally, I think the model likely to be most successful is the higher-end tier. I know someone whose starting price for an app is £15k. Not only do you get better clients, you aren't dividing your time between too many different clients and projects, and you have less chance of working with people who will complain or need their hand holding.