I'm not sure how that holds. As much as there is value in privacy/anonymity there also is a lot in transparency.
I find myself mostly in agreement with your view that a private ledger could complement a public one but I'm not convinced this is sustainable if we somehow become able to transact privately within the public ledger.
That's the thing though; you can never transact privately when you start with a public asset. You can obfuscate the origin, kind of like proxies do now with internet traffic, but you can never have a true private asset. Bitcoin has what.... a headstart of a million users? That's nothing. There are still 6.998 billion people on Earth who don't use cryptocurrency.
I do see a future with a public and private ledger (perhaps even a good programmable ledger), but I am not sure which one will be more valuable. Ask yourself... if you were a powerful company or government, how much would it be worth to you to keep trade/state secrets?
Please do not fall into this mistake of inferring Bitcoin's superiority on the basis of its userbase.
The headstart is much more than a simple number of users. It is a complex history where time, trust and capital growth are much more important than a simple assessment of its userbase. A very organic process which can scarcely be reproduced.
Have you contemplated the idea that by purchasing Monero through either fiat or Bitcoin you are also "starting" from a public asset?
