And people could just do all their business in cash to avoid banks. But that's not practical just like avoiding exchanges and not using wallet providers is impractical.

Normal people cannot function in a cryptocurrency ecosystem without these new tech middlemen. This is exactly what I mean when I say _in practice_. Average people are still left to the whims of cryptocurrency corporations that are worse than banks because they're unregulated, much greedier, and much less risk averse.