Cancel culture & Universal identities
Your Holy Grail of "cross-dimensional customer data. Imagine merging customers shopping data beyond Walmart, learning about customer spending habits elsewhere" ... scares the daylights out of me. That is my own personal hell you've just described.
I suggest you may want to look at so-called "Cancel Culture" through the lens of "accountability, finally". I've read elsewhere, "When you're accustomed to privilege, equality feels like oppression." To those claiming to have been cancelled, I ask, upon whose backs have you have built your platform?