There's an alternative theory about why Social Media sucks I'd like to ask OP their opinion about. It might sound a little elitist or exclusionary, but it rings true for me.
Why does Social Media suck? Maybe it's not because we don't have the right commercial entities running it. Maybe it's not because we don't have the right government rules regulating speech on it. Is the real problem with Social Media (and modern technology like idiot-proof cell-phones) that it's now possible for every low-IQ idiot out there to provide their (almost always) useless opinions to more people than the qualities of their ideas merit?
To make a long conversation short, most people are not that bright and have no serious useful ideas to add to any discussion outside of personal discussions about family and friends. When it comes to political discussions as an example, most people can (at best) parrot slogans they hear from politicians. Yet the Internet is flooded with political opinions anyway.
Why was the Internet a haven around say 2003? It's because most dumb people didn't have a computer with Internet access yet and it wasn't accessible to the average person. The Internet was great only when the idiots of the world weren't on it. You didn't need complicated rules or structures when the average online user was a smarter person.
4chan (despite whatever flaws it has) is still relatively good for some types of discussions because the immediately unintuitive UI makes it relatively inaccessible for dumb people.
HackerNews is relatively good because while the UI is pretty good, the culture and topics discussed make it inaccessible to dumb people.
Is this accessibility the real issue with Social Media and the Internet in general?