Maybe I'm in a middle generation? I'm certainly comfortable with programs where you have to save to a file, but for as long as I can remember, always every program I've used that doesn't autosave warns if you try to close it without saving. Web apps mostly autosave these days, but those that don't will also usually trigger the browser's "you may lose changes, do you really want to navigate away?" warning.
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.
Author here. That's a standard dialog built into the browser, which of course was implemented from Day 1. The problem is that people leave tabs open for indefinite time, the browser regularly saves memory by emptying old tabs and then it's gone.
Having started with files, I’m still sometimes worried to close a tab/app because I’m not sure it has saved the changes. Like when I write a text somewhere, but I copied in my clipboard before closing, just in case.
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.
This was by design.
Made possible once a generation existed who never used a regular filing cabinet.
Some day we'll look back on this era and think it was quaint that we designed our tools to destroy your work by default.
That assumes that software tools will start increasing in quality at some point.
Reality suggests the opposite is more likely to happen, and people will look back on tools today as 'things were better back then'.