Thanks for long list of references. I doubt I will ever get through all those!
My guess is if Bitcoin was as private as Monero, there would be alot more severe backlash and resistance to it from government / authorities. So we'd end up having something that would never get mass adoption, or momentum would be hindered which severely reduce its growth.

100% privacy isn't needed 100% of the time. So even if Bitcoin doesn't solve privacy issue completely then I could literally just switch to privacy coin as and when required. It seems like a good balance. 
Makes sense to me. 

If Bitcoin really isn't private enough, then over time, we will begin to realise this practically and switch to Monero or different alternative privacy coin. In reality I think people will opt to give up privacy in the case of Bitcoin because it is the largest decentralised network in the world, which makes it more secure and much bigger than Monero. Therefore Bitcoin perceived as safer. When we really need the privacy which clearly isn't 100% of the time, switch to privacy coin.

From my understanding Monero isn't going to zero so will always be around. Even though it is smaller decentralised network than Bitcoin it still serves its purpose when privacy is number 1 priority and Bitcoin falls short o  that particular instance whatever it may be. Because of its smaller size (market cap / size of decentralised network etc.) compared to Bitcoin it locks out the massive companies corporations. So the individual self sovereign still wins. 

Monero is a better privacy coin than Bitcoin hands down. But that doesn't mean Bitcoin wont be the main no.1 cryptocurrency used across the world, ubiquitous in every country.
That's the way I'm seeing it in my head. 🖖