They were until 2003 when they were classified as information services. The FCC then enforced net neutrality rules by penalizing ISPs whenever they broke them until 2014 when court ruled that if ISPs are under Title I, the FCC has no control over them. In 2015 FCC reclassified them back as Title II, in 2017/2018 Pai reclassified back to Title I, but multiple states (I know that at least California and Washington) implemented their own net neutrality laws.

And since 2015 social media platforms have had no real competition.

I used Facebook in 2006 and it already was taking over MySpace. I don't know where you got 2015 from, because how ISPs are treated has no impact on social media.

2015 came from the parent comment. I'm saying the current tech platform powers got a lot stronger in the last 4 years.