It's true, the first speculators of Monero are transferring public assets into the Monero system (unless they are the lucky ones mining pure Monero).  But as the economy grows, goods and services will begin to be traded for Monero and these will be truly anonymous.  
  
As far as your initial point, let's first go back a *scant* four years to 2011:  
http://www.digitaltrends.com/android/iphone-overtakes-blackberry-to-become-top-phone-for-business-users/  
  
Secondly, let me take you back to the year 2008.  Something amazing happened that no one expected.  No, it wasn't bitcoin:  
  
http://www.zdnet.com/article/facebook-overtakes-myspace-globally/  
  
Let's go back a decade before that:  
  
http://www.wired.com/2009/09/0928ie-beats-netscape/  
  
Now let's step back a century:  
  
http://www.somdnews.com/article/20140108/NEWS/140109402/a-century-ago-autos-began-overtaking-horses&template=southernMaryland  
  
All these things required a superior replacement to disrupt an established competitor.  In some cases the original asset paved the way while the successor inherited the fruits of that labor with a refined version.  
  

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Now again, I don't think Monero will completely replace Bitcoin (assuming it gets its shit together with blocksize issues) because a public ledger is valuable too.  But if you're only argument for why bitcoin is better is because "more people use it" in the face of overwhelming technological superiority... well, that's not an argument that stands up to the test of time.