Im not an expert obviously , but it was put to me that Bitcoins market cap is 195x moneros give or take , and therefore means that you have a bigger "anonymity set" , which I take to mean getting lost in a crowd. 
With all of Moneros privacy features, it doesn't account at all for its small anonymity set, which because of it's low market cap (2 billion or so) and its strong privacy features , actually prevent large players from investing, and so the market cap will remain small , and so too will the anonymity set. 
 

 Maybe I'm misunderstanding something, but Bitcoin doesn't HAVE an anonymity set except in the most trivial sense of the word. Your BTC can be followed, forever, with automated tools. If it hits a KYC exchange, somebody is due a visit if it pleaseth The Man to do so.

While #monero, after it changes hands a few times, the list of possible suspects is far too long to investigate, much less visit, since most of them will be too small-time to be profitable to rob for the manpower and noise it will create.