This is a pretty old article (September 2014).
Although the number of bitcoins is finite, it doesn't automatically mean that bitcoin's price will shoot up if adoption increases. You could have bitcoins circulating at a faster rate.
wider adoption means more people spending their coins, but also more people holding their coins in the hope the price increases. and by the time wallstreet pops up and start with buying up plenty of coins the price will shoot up like a rocket.
No one from Wall Street will invest heavily in Bitcoin. This is a vain hope. Unless they (miners) raise the limit and do something with the halving, Bitcoin adoption rate is doomed to stagnate. This doesn't necessarily mean that the price will collapse, but it will if just a few of the top Bitcoin holders decide to part with their stash...
And some of them most certainly will (for a multitude of reasons)