I foresee a collapse of BTC value when the first large financial institutions release cryptocurrencies of their own, which are actually backed by tangible assets like gold or by fiat currencies.
I'm afraid you still don't quite get it (you're not alone!) You cannot back a cryptocurrency with gold or fiat. You can create an electronic form of money backed by gold or fiat. We already have that. Just open your internet banking software to see it.
The whole reason a cryptocurrency is attractive is because it has no third party. That is what brings its cost down to near zero and, more importantly, makes it essentially impossible to control or regulate.
If you try to create an asset-backed digital instrument, you need someone or something to keep that backing stable and ensure/enforce it. You need a third party. We've already seen such systems, and they are entirely different to Bitcoin.