Not necessarily Monero. Whatever comes to achieve that uniformity best because it greatly reduces friction on that dimension. There is already better tech available, but no/poor implementations of it. But of course that is only one of several ideal properties of money. Maybe it is impossible to excel in all these properties for p2p digital cash because some are mutually exclusive (privacy vs auditability)

Any white market adoption is less relevant imo. Because of increasing onerous regulation Bitcoin will be squeezed into black markets over time, and whatever usage allowed on white markets will be greatly limited and in a neutered form. White market acceptance might be nice to have, but is at odds with the whole point of Bitcoin: Permissionless money.

"White market trade, by definition, requires permission, and black market does not...Any person operating in the white market requires permission to do so. Bitcoin is therefore inherently a black market money."

While arguably easier for many, you don't need on/off ramps (and for some it is not even preferable (noKYC crowd) or possible to begin with (cash cultures/unbanked large populations of the world)). Off the top of my head you can always swap from other crypto, sell things, offer labor/services, or take advantage of jurisdictional arbitrage. I'm sure I'm missing more.

For sure agree that big data and NSA spying is a problem, but not insurmountable. For example, encrypted messengers and VPN services (yes, most suck) have become very popular as a direct result. USPS postal services deliver millions of illegal packages/letters (~16 billion just this holiday season). Even from within, these systems flail for control. Darknets couldn't do it without them. I suspect you don't think it is all hopeless either though, otherwise you wouldn't be bothering with Bitcoin.

Private p2p digital cash can only protect you on one side of a transaction. It's only part of the solution, but something that wasn't even possible before.