One of the "eternal September" moments of web app development was in the late 1990s when Microsoft went "all-in" and Microsoft-oriented developers flooded forums with tearful laments about how "MY BOSS NEEDS TO ME TO BE ABLE TO ACCESS LOCAL FILES IN A WEB APPLICATION!"
From the viewpoint of a web-native developer though, you need local files about as much as Superman needs a Kryptonite sandwich. (You didn't lose local files, you gained the universe! Look at how multimedia software on CD-ROM was utterly destroyed by the world wide web!)
That image sorter, for instance, has a million images sampled from a practically infinite pool all available instantly to any device anywhere in the world that's attached to my TailNet -- though you'd better believe I keep RAWs from my Sony on local file systems. [1]
I had a boss who ran a web design company circa 2005 which had a great spiel about how with web applications small businesses could finally afford custom software, I had my own technical version of it which went something like. "Back in the Windows '95 age obsolete desktop applications kept their state as a disorganized graph of pointers that inevitably gets corrupted just like cheese goes bad and crash; modern web applications keep their state in a transaction-protected database (if you're smart enough to NOT GET SEDUCED BY SESSION VARIABLES PROVIDED BY YOUR RUNTIME) so your application state is refreshed with every page update"
[1] Adobe's relationship to the local filesystem drives me nuts even though I've talked w/ people there like Larry Masinter and deeply studied file formats enough to understand their point of view. My first instinct, having worked at a library, is that you want to associate metadata with an object, in fact I really want to "name" an object after a hash of the contents and have the object be immutable.
On the other hand, XMP which stuffs a metadata packet into a file, is a good fit for the way people use desktop apps. Still, my #1 complaint about Photoshop is thinks a file has a changed (some metadata has changed) when I do some operation that I don't think of as a mutation such as making a print or exporting a compressed and scaled JPG with the "Save to Web" Dialog. Since I do a lot of different things with my machine I am always forcing shutdowns which means Photoshop is always harassing me to recover files that I "didn't save" even though I didn't really change them. Sometimes I just save files that I don't really want to save but it feels icky because the source file might be a JPG which might not round trip perfectly, where I might feel compelled to save at a higher quality than the original file and all of that.
