I just started using CapRover (https://caprover.com/) for hosting some side projects, it was extremely easy to set up and appears to work similar to how Flynn.io used to.
I think another aspect of it is the auto industry's reluctance to admit that cars are dangerous. Before seatbelts were introduced, manufacturers didn't want to include any overt safety systems, because they introduced the idea that we needed protection from the cars. There were no dangerous cars, just bad drivers. There's a great 99% invisible episode about it: https://99percentinvisible.org/episode/nut-behind-wheel/
Why in the world would they do that? Can't they just launch a normal browser window or something? Downloading 500MB of chrome bloat just to display a login window seems ludicrous.