However, existing tech giants have little reason to do so, unless users vote with their usage (which is sabotaged by lock-in effects through the existing social networks...)
You're right that Uber Eats is not yet a monopoly. What I meant is that it's the kind of platform that eventually turns into one, and wouldn't exist if that wasn't the goal. The phrasing is still wrong though.
The open standards don't protect from the "Big Techs". See AWS and the open-source technologies that they use. "Tech monopolies" is the too broad category to create working solutions. Some monopolies use the network effect, like Facebook, Twitter, Uber, etc. They are protected not by closed technology but by the community. Building an app like Uber is much easier than making a company like Uber. The same applies to smaller companies/services like Reddit or even HackerNews.
AWS is indeed not the kind of platform this is about. They enjoy some network effects, but have little control over them. AFAICT they're mostly winning on execution.
Amazon's API mandate is in fact one of the things that inspired me to write the post.
You're right - I've meant they benefit much from the open-source technologies, and forcing them to support/use only open source technology wouldn't harm them much.
Even very rich tech companies struggle to compete with them. Supporting the open source isn't enough.
Could you explain how you would "obstructing interoperation"?