So if someone buys hardware to mine bitcoins, the manufacturer is either screwing them, or being charitable. Which one of these is true, or am I missing something obvious?
The purpose of mining is to secure the network and process transactions, and to generate a Bitcoin income for the miner..it just so happens that Bitcoins carry a value (substantially, lately) in fiat to turn that virtual income into "real world" income.
You touch on some points to a more complex situation. The vast majority of people purchase mining equipment (CPUs, GPUs, FPGAs, and now ASICs) with the intent to generate an income for themselves. The crux is that a miner can't ever be
truly certain that they will generate an income for themselves..given that there are a multitude of factors at play (future difficulty, number of total (and future) miners, individual hashrate, value per BTC, etc). It could very well be that every Average Joe and their friend will buy an ASIC if USD/BTC is $1000+ ..or it could just as well be a small dedicated group of geeks mining away if USD/BTC is $1.
That said, the manufacturer doesn't know where the future of Bitcoin will go. If they built their businesses around mining on the hardware instead of selling it, then I'd imagine the value of a coin wouldn't be nearly that much because it would mean competing to mine would require a substantial amount of capital for custom made chips. Centralizing the mining power (assuming BFL and Avalon solely built hardware to mine on) doesn't bode well for Bitcoin and defeats the purpose of its creation to begin with.
On the other hand, if they sold the equipment to the masses they may stand to make more money in the long term..assuming continued community support, a competitive product compared to others on the market, and a willingness to continually develop better products. There's a 100% chance for the manufacturer to make money if they sold the equipment to others..compared to an unknown percent if they mined on the hardware themselves.
It's essentially the same scenario as the 1849 Gold Rush...why dig for gold yourself when you can sell tons of shovels/equipment to the prospectors