OK, I don't wish to get bogged down in this, but your point has sublimated from 'most homes own an iPad' (stated twice) to 'most households in large cities have access to a computer of some sort'. Not a subtle difference, and entirely sidesteps the issue that the iPad is being used for specific education purposes that a home desktop PC shared with the rest of the family cannot meet.
Anyway moving on... meanwhile, in the UK:
http://www.guardian.co.uk/education/2013/jul/28/ipad-tablet-computer-school-parents
Haha, that's what happened when my old primary school got MacBooks
----------
Why? Most other industries are being computerised... Why not education?