And then the kids will move on to the next thing. Hopefully, for the sake of their investors, that happens after they've been acquired for a billion. Rinse, repeat.
However, note that everything you read is not necessarily true. Unless you have HARD DATA, whatever you read may very well be made up.
"Didn't people say"
Twitter is an indispensable communications medium that has more than 1 use case (read news, talk to friends, overthrow a government, etc). Thus ads makes sense (and I would even pay a low, yearly fee to keep it around).
Snapchat is interesting, but $100 million interesting?