> I don't understand what problem email can solve that mail cannot.

I think it's a wrong example. Email provides light-speed delivery, dirt-cheap cost, and brain-dead convenience on top of also being able to mail. So email actually never competed with mail.

Web3 is yet to strike any decisive blow against today's web (or it may never). It's more like another part of the web.

> Transferring money was in seconds, compared to Fidelity/Venmo which took 3 days!!! - Very easy to loan money against crypto holdings vs stocks - ResearchDao's like ResearchHub

For a smaller amount of money (<$100k), banks already can transfer money within seconds. I've seen people sending $1Ms only using their phones, but, IIRC, you need a good record to do that.