I need to side with GMail: Over the last year or so, email has turned into a cesspool. No one even reads it anymore.
Every week someone who I've never heard of adds me to some pointless email list that I never wanted and will never read. My inbox is constantly clogged with notifications that I never asked for, and don't care about. Every time I open an app or buy something from a website they think they can send me pointless emails forever.
The bigger problem is a lack of regulation: Because there's no rules, everyone needs to fight to keep their email at the top of the queue of unopened emails.