Even if Bitcoin holds the long term uptrend through the next couple halvings, it'll eventually break down. I don't see why entering a bearish supercycle (years or decade-long bear market) would change the bigger picture though. It's the same thing as the 2011 or 2014 bear cycles, just on a larger scale.
Bitcoin is provably scarce. If the demand keeps growing for such an asset them its value will also keep growing.
But I agree that it will eventually break down, if there was an asset a lot better than Bitcoin. So far, there is none.
Key words: "if the demand keeps growing"
Even if Bitcoin is superior to all other forms of money, it isn't guaranteed endless demand. There is a limit to the amount of value that can flow into BTC, even if that limit is theoretically when every other possible type of money is valued at $0.
In all markets, equilibrium is eventually reached and overall trends reverse. Bitcoin is not immune to that, no matter how good it is.
No, of course not. But observe where we are in terms of rate of adoption. Bitcoin is still very young in that regard.
Plus scarcity, as perceived by us, also increases demand, and Bitcoin is provably scarce.