the festival experience has been/is great, but honestly, I get enough for just seeing 1 band locally, play a 90 minute set. Or even less. If certain bands don't come to my town, I either try and find a way to see them in another city (like Chicago for example, which is close to me, plus my brother lives there), or I honestly find other concerts to see and be happy about that. I suppose if I lived in a very rural part, or a city that rarely had touring acts and the local scene wasn't all that good, the festivals might hold more value to me.
But more specifics about the fans and types of music. I do follow how the majority of the ticket buyers want a can't miss, which in the interest in being able to break even, usually must be artists who are more conservative. But if that were not an issue, the idea of a festival that had progressive rock in it, but the artists themselves aren't necessarily only considered in that genre, would be ideal for me.
The music that is "being progressive" or at least is very difficult to categorize, or call "prog" is actually, to me, the music that is being the most "prog" (or progressive) in a sense. If a festival was put on like that, hell even if it only took place once every 2 or 5 years, I would be a lot more intrigued by right now. I'm still not sure I would go, just from the argument of the financial side and the fact I have enough music and entertainment to use that $ on at home.
And the anticipated audience numbers would likely not be what many of these festivals have. Not the size of Nearfest or ProgPowerUSA certainly. But as an example with PP, the 1st one was held at, in-effect, a bar. And I actually find it still the most memorable of the ones I've attended. Maybe that's just coincidence, but there is something to be valued in, value, lol. When things are more stripped down, and underground, it can and did feel really special.
If a festival was small but unique, it likely would feel special like that.
But the chances of a festival being set up, featuring college-prog, technical death-metal, power-pop and bluegrass music, all in one, are almost unfathomable. In theory, that would be wonderful, but that's why I would never deny I'm a victim of my own taste. And the numbers of people who enjoy or who would be interested attending such a festival is very small. But even say, just one of them. I would love to see a festival that featured all college-prog bands. It probably wouldn't be called that, but the bands do have an audience. Many of them do tour, but then again, many do not. Just see Oceansize, who only came to the US once, in 2004. I'm not sure they would have been up/been able to still play a 1-off or 1-off plus a few select dates in the States, and break even, but if they could, a band like that would probably draw people to travel for and come to such a festival.
The same might be said about some of the technical death metal, or even Post Metal groups who may only play in their area, or perhaps they are able to get on a tour once or twice every 10 years. Maybe more of the "projects" even, instead of the main groups who those sideprojects include. I'm thinking of bands like Sculptured, Subterranean Masquerade, In Vain, etc.
But I think it's a valid point about these bands not being aware they are "prog" or how there are festivals for prog. They are just rock music, and if they play live, they tour with other rock or metal bands, prog or not. And even if they don't play live all that much, it may not be their intention. With DIY being something being done more and more, the live experience may not be what it once was, even with festivals. Who knows, and who knows how far away that may be sadly.