Problem is that Google tried to have it both ways. Android is technically much more open, but then they would make deals to squash any other competition. It’s exactly the un-openness that Google’s gotten in trouble for.
This article lists a bunch of the special deals Google made with various companies in order to prevent competition https://www.theverge.com/23959932/epic-v-google-trial-antitr...
> One Google Play exec boasted she got Riot to halt development on its own app store by promising the company $10M in marketing.
> Another Google exec suggested that sharing revenue with Samsung would be “better at disincentivizing other app stores from being preloaded.”
> Google wanted to offer a 16 percent Google Play revenue share to key Chinese OEMs to “secure Play exclusivity” — and wound up giving them 20 percent.
> A secret Google deal let Spotify completely bypass Android’s app store fees
Apple made significantly less of these deals - they have their rules that you can either follow or not participate. I do think that some of those rules limit competition and make worse products for consumers.