The rivalry between Google and Apple has defined the mobile experience and the smartphone industry over the past decade, but they remain dependent on one another in many ways too. For instance, Google is still the default search engine on the iPhone and iPad, something which costs the web giant a huge sum – up to $3bn this year alone, according to calculations by Wall Street analysts Bernstein. Bernstein used legal filings, third party research, and its own estimates to work out the price tag for staying on the iDevices – with all the search traffic and associated revenues that position brings. “Court documents indicate that Google paid Apple $1bn in 2014, and we estimate that total Google payments to…