Being muscled out?

Dear teachers,

The following is an excerpt from 60 minutes.

(sources: https://www.cbsnews.com/news/brain-hacking-tech-insiders-60-minutes/)

Could you please let me know the meaning of "the body builders on the beach are being muscled out by small companies" in this context?

We reached out to the biggest tech firms but none would speak on the record and some didn’t even return our phone call. Most tech companies say their priority is improving user experience, something they call “engagement.” But they remain secretive about what they do to keep people glued to their screens. So we went to Venice, California, where the body builders on the beach are being muscled out by small companies that specialize in what Ramsay Brown calls “brain hacking.”

Thanks and best regards,

David Kim