It's actually about half of that. About half of those people shouldn't have found blocks and only did because the person who should have mined the block was working on the other chain.
Think about it this way, for each block in the fork, someone mined the block in the 0.7 chain and someone mined it in the 0.8 chain. About half the time, the right person got it (because the forks merged when the work in them was roughly equal), and they still have it. About half the time, the wrong person got it and the right person lost it in an orphaned block.
That's not true. Think about it this way - the difficulty didn't change, so on average everyone mined about the same number of blocks as they would have if the blockchain hadn't forked, except that all the blocks on the losing side of the fork were orphaned and the people mining them didn't get paid. If it wasn't for the fork the blocks would have been distributed slightly differently amongst the miners on the losing side and they might have received very slightly more or less, but since it could vary in either direction we can safely say they're out 625BTC or 29k$. (This also means all miners on the losing side of the fork lost money even if none of their blocks were orphaned, since they could potentially have mined blocks if the chain hadn't forked.)