Yes because those who are already involved in bitcoin and also listen to what other people tell them are more scared of the FUD telling them that bitcoin is going to dump. They are also greedy thinking they can buy at the lower price (namely $20k that was being advertised in their FUD). Which means a simple bio change of someone who has been tweeting a lot of positive things about bitcoin is not strong enough to change their minds.
You're totally underestimating how much influence Elon Musk has. There's a reason why $TSLA is astronomically overpriced.
As for all those apps, I don't know all of them but many don't affect the bitcoin price at all. For instance you can buy millions of bitcoin on PayPal or dump millions and it still wouldn't change bitcoin price because it is not linked to outside world specifically exchanges.
They do, even if we like it or not because not every single exchange outside the de facto cryptocurrency exchange allows trading of crypto CFDs. They do allow their users to trade "real" bitcoin, it's just that they're not withdrawable with some platforms.
I name exchanges such as Coinbase, Kraken, Bitstamp, Bitfinex, Gemeni, etc because they are the main source of price and the price is decided there not elsewhere. Even Binance has very little effects since it is mainly an altcoin exchange and it has tether market not fiat market with a huge portion of their volume being fake.
That's not how markets work. USDT has a sizeable chunk of the total trading volume whether we like it or not, and Binance DOES have a huge effect. Even Binance's BTC/EUR trading pair, a FIAT trading pair, is #11 in terms of trading volume.