That will happen when commodity product purchases can be done using these alt coins as much as they can with BTC.
That is the big holdup. Right now BTC can be used for day to day money transactions, where as Steem, LTC, BCH, ETH, etc, are just now breaking into the daily transactions.
What value is any core when you can not buy anything common with it? Limited.
The early adopters like Overstock, Pirate Bay, and others, is what gave value to BTC. I am now looking for the same value adder to these other alts.
So far I see BCH and ETH being the next contenders to dethrone BTC. However, that can change at any time.