Re: Big fines are just a cost of doing big business
If you compare this fine with the one recently levied in the UK on Facebook I think you'll appreciate that there are differences. Plus, non-compliance will lead to daily fines of up to 5% or global turnover. This is definitely enough to get Google to comply.
I suspect that, given a choice, many users will happily install and use Chrome, GMail, Google Maps, etc. The comparison with Microsoft and Internet Explorer isn't perfect but still interesting: Microsoft had largely stopped working on the browser and was actively attempting to prevent the development of HTML; even though it's market leader, Google is still actively developing Chrome, which it hopes at some point will become the runtime of choice.
I also think that Google's own Project Treble may have been designed with this decision in mind: offers users the prospect of receiving updates more timely but also cements the role of Google Play Services even as it makes AOSP more attractive to some manufacturers.