In my opinion, the reason is purely economic. Writing software in web frameworks (even a phone app, which is often written in javascript and runs in a separate browser which takes up to 300MB of RAM at the very start) is much faster, has a less steep learning curve, shorter test loop, and faster and easier release cycle. Additionally, recently every company has tried to move to SaaS business because it's giving more steady income (pay 60$/month or 10$/month but with a promise to pay the whole year, which vendor-locks a user)
While I've been involved in releasing both types of software (a ye olde Windows standalone app written in Qt framework and the new software that's being released every 2-3 days or so) I find the new way much less painful. I couldn't imagine releasing a Qt app in such a cycle (how to do updates? maybe like Minecraft - every other launch there's a new package of 64MB downloaded)...
...but as a user, I feel much more comfortable when code is on my computer, available for me to run. While extensively using Google Docs to share documents with my wife (calendar, spreadsheets) and band (songlist, lyrics), I'm scared that if I moved everything to on-cloud (paid mail, photo enhancing (thankfully I'm a standalone Lightroom buyer), vector graphics (inkscape user), photoshop (gimp user), etc.) one day I would hit the roof in payments of my per-month-but-bound-to-year plans. In 2030 it would be also netflix, shmetflix, televisionix, phonix, car-as-a-service, heated-seats-as-a-service, air-conditioning-as-a-service, toilet-as-a-service, smartwatch-as-a-service etc. building up to an unbearable rent for something that used to be free or paid once. I don't feel like my duty is to provide a constant supply of money to my beloved corporations