Until iOS's market share starts shrinking to a small percentage of the population, and Google will give them the Windows Phone treatment. And then a subpar Google experience on iOS might push iOS users to Android. It's just a matter of getting the timing right.
It's just as likely to push people away from Google services.
The majority of people using iOS are not financially invested in the google ecosystem - they're more likely to be using the free services like search, email, maps, etc.
If a google service doesn't work well on the $700 phone you've just bought that runs 5 years worth of purchased apps, are you really going to abandon all of that because of a free service?
No, you're going to find a service that works better on the device. There are very few if any things where google is the only provider or even the only good provider of a service.
