Two things: one, volatility isn't anywhere near ending. And two, Cardano has good roadmap and are almost achieving their next milestone, but just as @jvdp said, market capitalisation is very important. And I would add that bitcoin has the advantage of early starting and has quite the mileage already... for Cardano to catch-up in such a short time frame, more efforts needs to be put into it and thats like working round the clock for the next half decade before they can have the attention of the masses and not worry about price inflation, volatility and regulations. Because their 3rd Gen identity makes people look with so much curiosity and anticipation.
As of today,
BTC is 22,534 times greater than ADA in current price.
Price difference:
ADA: $0.351517 USD
BTC: $7,921.23 USD
24hr Vol:
BTC is currently 12+ times the value of ADA in daily trading volume.
ADA: $734,804,000 USD
BTC: $9,478,720,000 USD
So in prospect, ADA looks great on paper and the dev team are working hard to ensure it's a reality, but practically now and through 2018... the speculation would be faulty because of the wide range of factors.