From where I sit, smartphones completely ruined the internet.
If you're defining "successful" in the sense of people-making-a-lot-of-money I completely agree.
If you're talking about the internet in 2005 vs 2025, smartphones completely ruined the internet. At one point I had half my high school using HTML in their AIM profiles because they thought mine was cool.
Now kids can hardly even type on an actual, physical keyboard.