This is the fallacy in your argument. No one is claiming Bitcoin will go up forever. But that or a bubble that pops back to zero are NOT the only two alternatives. Bitcoin could go up and up for a while, then go up more slowly, then plateau, then go up only to catch up with the inflation of the fiat currencies against which it is compared. That's quite a feasible future, just not in you religious, authority-inspired outlook.
What you basically are saying it will go up forever. Just at different speeds?
That's still the same issue.
Yes, I can point you to other things that go up forever, just at different speeds. Human population, for example, or the rate of devaluation of the USD. This really is no shocking surprise. The basic problem is that you're arguing from two positions (today) that are rather infantile: 1) There's this article that says here's how you can tell you're in a bubble (appeal to authority) and 2) if this isn't a bubble, Bitcoin will just keep rising at this rate forever (strawman).
You do a couple of other tricks that have been fairly well understood since the inquisition, like reversing the onus of proof.
This is quite plain for anyone who understands the mechanisms of fallacies. Google Carl Sagan's Baloney Detection Kit.
What you are specifically NOT arguing is how or by what mechanism Bitcoin will fail. If you were, that could be an argument worth having. As it is, it's like trying to argue the existence of god against a devout Christian, a complete waste of time.