Sorry, but the naivety of this caught my eye. "I know of artists who have taken a list of every folk club/festival organiser/arts centre booker they know of, pulled a day aside, and rang/emailed each of them, detailing their act, their availability and their rates. Within the week, they had a 20 day tour at £500 per gig, up and down the country."
In the interests of public understanding of what really happens:
1) I have a list like that. There are 1175 entries (including arts centres, village halls etc).
2) In one day you would only get through to about 15 if you were lucky. There rest would be out, busy, wrong number, moved jobs, bounced email etc.
3) Of those, only one or two would book an act they'd not heard of before. The rest would ask for a link, cd or other reference, or just find some way to say no thanks (most would be booked up over a year ahead, with an existing list of waiting acts).
4) Organising a tour takes a very long time. You need to set realistic driving distances between gigs, and many venues only operate on a specific night of the week, or day of the month. There are also time and distance limits between gigs and previous/later tours to consider. It's a very difficult juggling act, finding, holding, and confirming gigs at the right moment at the best price. Setting up a 20 day tour (even when you are pushing at wide open doors) can take weeks of negotiation, calculation, persuasion and downright deviousness. In one day of hard slog you'd achieve very little and go to bed with a headache.
When I was working full time, as our agent I matched every hour I spent with Tom, rehearsing, driving, hanging around away from home and actually playing, with an hour at my desk. I'd ring about 15 people every night I was home, and more in the daytime if I knew people would be in. Then there were the contracts to print, email and sign, photos and press packs to go out, maps to print (this was pre-satnav), safe houses for day-time warmth and maybe a snooze, accommodation if not provided by the venue, and then all the mailing list and other promotional stuff on top of that.
This is why agents are not interested in breaking acts, and I for one don't blame them, Frankly, there is only time in the day to handle one act, and no-one will be as hungry as the act itself. Established big names are a different matter, but even then, there is a huge amount of work to be done for a 20 day tour.