I think in this context "competing" means having a meaningful market share, which would help reduce time the world spends on the alternative useless gamified/addictive apps

And if it gets meaningful ”market share”, the business incentives are pulling in the direction of growth, which is the articles point.

In many segments, especially ones served digitally, only one or a few companies will survive. It's very much "grow or die".

Pardon my ignorance but is that expensive to run a social platform?

Running a social media platform can be very expensive, and it only gets more expensive every day.

Media takes a lot of storage and bandwidth, and you basically have unbounded costs if you want to meet user expectations for posting media.

That's a narrative that makes no sense. If a company is profitable, it doesn't "die". If customers like your product and their friends are on your platform, they have no reason to leave to another.