Bitcoin is a pure Ponzi scheme, the intrinsic value is zero. That is not to say the price must necessarily converge to the fundamental value of zero in the long run. Given the energy usage, I think this will be the case though. Nobody can tell you how much longer the price is going to increase. Also, look at transaction fees, Bitcoin is not very efficient.
The analogy to gold is wrong because, at least for some people, gold has intrinsic value.
Modern currencies like the dollar are not backed by gold either, that is fiat money too. However, you can pay your taxes with dollars, that is the fundamental difference. This is why next year, a dollar will still be useful, a Bitcoin might or might not be useful.