Problem #2: It's expensive to support millions of users who post shit
Problem #3: Twitter's revenue base is too small for its cost base
Solution: Eliminate advertising and charge $20 per 1000 tweets. Free to read, costs a tiny bit to tweet.
People who post shit will disappear. People who have an audience and something to say won't bat an eye at this low cost.
If this weeds out 80% of the shit while keeping 80% of the good stuff, Twitter will simultaneously shrink their costs while growing revenues to become a sustainable business.
With this model, Twitter is a $1 billion per year profitable business [2] with a much higher signal-to-noise ratio. [3]
Improve the signal-to-noise ratio and Twitter becomes THE place to be for all kinds of communities. That means a return to growth and higher rates per 1000 tweets.
[1] https://en.wikipedia.org/wiki/Sturgeon%27s_law
[2] Start with 200 billion tweets per year. 90% are shit, and 80% of these go away, leaving 36 billion shitty tweets. 10% are good, and 80% of these stay, leaving 16 billion good tweets. 52 billion tweets in total, monetized at $20 per thousand is a billion bucks a year.
[3] Signal-to-noise ratio before is 1:9, after it's 1:2.