What is stopping apple from creating a built-in social media app for iPhones and becoming probably the biggest social media company?

They have the technology and years of do’s and don’ts experience by looking at other companies successes and failures.

A huge percentage of world population uses iPhone right; mostly USA and European countries at least.

If the keep the goal on just creating an Ad free social media app that comes along with the iPhone pre-downloaded then that would lead for more people (android users) to enter the apple ecosystem.