Can BTC become as fungible as XMR?

Do you think XMR fungibility can make BTC lose marketcap due XMR gaining a lot of what is in dark market action?
Didn't XMR had problems to scale that couldn't be solved?
What happens if XMR reaches higher transaction volume at BTC's level, isn't this a big problem for XMR?
And finally... can BTC eventually render all those anonymous niche coins irrelevant thanks to increased privacy like CT and mimble wimble stuff?

I was considering entering in the XMR market since im not sure if BTC will be able to become anonymous enough, but at the same time, im not sure if it will be viable for XMR to function with actual usage since it seems their blockchain has serious speed and bloat issues, then at that point it will not be a competitor against BTC with the improvements in privacy which should be enough for the people that use dark markets...

I would like gmaxwell's opinion since he is the expert on this and was also holding some XMR I think.

I just don't know if this is all hype fueled by news without any technical fundamentals into it. Maybe XMR has developed a solution to scale that I have missed?