I don't think anybody knows exactly what's behind the curtain, but many suspect Wall Street price manipulation after introduction of Bitcoin futures markets. Presumably, while they were wrecking the price on exchanges, they were buying on OTC markets.
So As you think, Is their arrival is a must for Bitcoin price goes up again?
Even if not them, others would come. Despite Bitcoin being on the media front and center for quite some time, most people are still not familiar with cryptocurrencies.
Why Wallstreet doing this price manipulation in the cryptomarket as you think? what is their purpose to do so? I have a different idea?
It's for the same reason that they do it to gold. They want to discourage people from trying to hide their money away and protecting themselves against inflation. They want people to use fiat indiscriminately, without fear or doubt that their money is using value. However, many people are fed up with seeing their money become useless over time, so they turn to bitcoin, gold, etc.
I've noticed a bit more suppressed price action on the charts lately, like it seems that some levels are being defended. It's common for central banks to do this with their currencies as well. The Swiss national bank has been manipulating it's currency for years, defending it from the 0.95 level, because people tend to buy it as a hedge. So they devalue it in order to protect their economy.