After the schematics are released every country with lax copyright laws will start churning them out.
The schematics are going to be pretty simple, there's not much on the board. A competent engineer could design something similar in a day or two of work. People are interested because it will tell them how their hardware is working and how to work with it and integrate well with it. If folks are interested in cloning it, they've already started design work, likely around a different chip.
It's perfectly possible that someone can make similar boards and turn enough profit to make it a viable business.
If the Foundation (and RS/Farnell) isn't taking a loss on the boards, then the Chinese should be able to do it cheaper without much difficulty. They're all about low-margin, they're good at being successful at it, and it would save a lot of logistics cost. I'm pretty confident it's going to happen. I also expect to see at least one of the other big SoC vendors jump in, my bet is on TI, but it could be ST or Renesas who have all spent considerable energy and money to capitalize on the maker/hacker/experimenter market - and who are also more vertical than the RPF can be, leaving extra room for profit.
You'd be surprised. There's enough people who would indeed rather save £1 than help a charitable cause.
I'd pay more than a £1 to support hardware that is actually free and open, much sooner than I'd pay a £1 to support a charity in a foreign (developed) country .
This is why companies like Broadcom are so careful with their technical details and are not likely to open source their drivers. It's the only thing stopping other companies from cloning their products.
Clones, pretty much be definition, would be using Broadcom parts. They'd profit just as much as they do from the official Pi, if not more, they're selling parts. By not selling to this market, they're losing the business to other SoC vendors that are more open. Though who knows how much they make on backroom competitor exclusion contracts.