because every attempt to create digital scarcity different from bitcoin is a shitcoin and trigger the paradoxes of scarcity cited prior. 
These paradoxes are conceptually hard to realize today, but they will be clear to all in the future, when the shitcoin hype will decrease (in reality, if you observe a historic price graphic of shitcoins/bitcoin you can observe already these processes in action). 

 "absolute scarcity automatically equals value" is a fallacy

Value is subjective. Value is a function of supply AND demand. You can't control demand. Any good btc maxi that is obsessed with austrian econ should know this 101 fact but surprisingly few do.

That should be plenty to at least ponder that you might be wrong.

https://github.com/libbitcoin/libbitcoin-system/wiki/Scarcity-Fallacy 

 I admit the possibility, even not so improbable, that even if bitcoin is a scarce resource could fails to detain value for some reason. 

I admit also the possibility that some shitcoin could detain value for long time like or better than bitcoin, but I consider it less possible than a scenario where dog-like aliens come to the planet earth in flying toyotas ufos singing taylor swift songs.