Gmail has folders; I have the same ones I used to have in Outlook. They're called labels, and the only practical difference I've noticed is that you can have more than one label on a message, unlike folders where a message can only be in one. You can nest labels one inside another and get a nice hierarchical list of them on the left just like Outlook.
Yes, it does now, and I can't for the life of me remember when that happened. But this was a capitulation after Google long insisted that tags were totally superior.
Notice there now are options like "Move to", which basically removes the tag for the current folder - I mean tag - and applied a new tag to let people treat Gmail mostly as if it is folder based, because as it turns out a lot of us insists on folders. But that functionality didn't use to be there. Both the nesting and "acts almost like folders" actions were added at some point long after Gmail was launched.
