Is there now a generation of users who never worked with files?
blog.hyperknot.com
blog.hyperknot.com
In my (I guess biased) opinion, this is a reasonable affordance to expect; throwing up a confirmation dialog is a lot less burdensome than implementing autosave. I would consider not doing so in this day and age an antipattern.
I remember when Sublime Text was showing me temporary tabs even after restart, and that was so cool!
But, while thinking about it, in real life auto save is the default: grab a piece of paper and scribble away. No need to give it a title to keep the changes for later.
Made possible once a generation existed who never used a regular filing cabinet.
Reality suggests the opposite is more likely to happen, and people will look back on tools today as 'things were better back then'.