Not having my emails in folders would make it impossible to skim an email "conversation" prior to picking up after 3 months. It would be impossible to archive a project and send it to people.
Foldering has its uses. Search has its uses. I do both.
What is this current fad for telling me how I must do things. I'm an individual, and I have strengths and weaknesses. My strengths don't match yours - don't make me work the way you think I ought.
And get off my lawn!