They say there's no guarantee it can be restored. Therefore they can't charge for it because if they did and couldn't restore, they'd HAVE to refund or at least in countries like the UK/US, they could be sued for a lot of money, and by refunding, they also have to pay refund fees (been in the position myself so I know this). Thus, they've lost money. To ensure they could guarantee 100% chance of character restoration or as close as possible to it, there'd need to be a TON more server space allocated (think of all the data each character holds, and they'd have to hold this forever), and that costs money. They'd have to charge more than a small fee (you're looking at $20 or more I'd say), to offset those costs. And the amount of people using it would be tiny if you ask me. So again, I don't think it'll make them money.

Of course SE knows the actual hard coded numbers, but we can work with estimates. And usually our estimates are around the right ballmark collectively.