Ok, you're lured me in for one more post!
1. Apologies, I wasn't clear. You're right, deleting an app deletes the save data if it's not iCloud. By 'good saving strategy', I meant iCloud games (which quite a few of my modern ones are), or putting game saves in the Documents directory for easy backup from iTunes.
2. However, I backup game data to PC/OSX from ANY game using
iFunBox. No jailbreak required. Simply drag/drop game saves to/from device. You can also get a peak inside the .app files too if you fancy a look at the GFX for some games!
3. It's very hard to find sales figures for iPad only games, so consider. Infinity Blade has 220,000 US reviews, and ~4 million players (1 US review per 19 players). Assume (conservatively) 10 players per US review. Real Racing 2 HD has 14,000 reviews ~= 140,000 players. PGA Tour 2012 (iPad Edition) has 34,000 reviews ~= 340,000 players. Galaxy on Fire 2 HD 5,100 reviews ~= 51,000 players. My estimates are intentionally low, but I doubt Almost Human would be too upset if they get 51,000 sales at £4-5 a shot. Not saying it's guaranteed money - but I'm also saying that there are a lot of cases where people have clearly made money out of iPad games!