I think there's also an aspect of people's expectations changing. Twenty or thirty years ago, no one expected new software to run on a ten-year-old computer and no one expected Windows software to run on a Mac or vise versa. (Linux was pretty far outside the mainstream.)

Now, we have a proliferation of computing environments, and it's hard to give people generic advice about how to install and use a tool that would apply equally across all those various environments. Browser standards seem to be the one thing that's relatively common across platforms, so a lot of that stuff moves online.