2) Uber would sue Apple for damages and try to get back into the app store & using its monopoly to influence other businesses.
3) Uber would encourage users to use Android and possibly raise awareness of Android and begin supporting its development in OSS circles. It would also support OSS projects that improve the app experience of web apps.
4) Uber would also start offering incentives to its api developers to make their own Uber apps for the app store as an alternative. So none of that referrals crap, proper cash incentives. Maybe even invest in a couple of startups creating these apps.
5) Undoubtedly Uber will use its PR team to write negative articles about iOS and use it as an opportunity to 'fight back' and gain customers. It will ask users to also write to Apple or ask them to boycott Apple products.