There are more than two choices as there are a myriad of smartphone makers, some developing their own operating systems. Mobile o/s are exactly a vibrant competitive market. Even if one strips Apple of all control over it's ecosystem, it will remain a very popular choice with people, (imo) despite the dozens of smartphone manufacturers and even though it's market share is dwarfed by Android.
Because antitrust and regulatory laws are needed, doesn't preclude from voting with one's wallet for mass produced consumer products made by for profit companies. It also, imo, doesn't mean that companies no matter what they produce should not be regulated to ensure what they produce will minimally not physically harm or injure people. But to me the line is drawn when government tells these companies their proprietary ip has to be interoperable. Voting with your $$$ is the best way to make companies see the light of day.