Android is perhaps the closest in comparison to Microsoft/Internet Explorer. Spin off Android into its own company, including the Play Store. There would be nothing stopping Google from keeping their apps in the Play Store, but they would sit on the same level as competing mapping and search apps, and users would choose which one to use instead of have it preinstalled.

That would be great. Android has a competition-destroying business model: giving away the OS for free, while subsidizing OS development with ad revenue from unrelated services. It killed companies like Symbian who just sold you an OS in exchange for a license fee, without trying to marry that to services you can't easily switch away from because they have all your data.