We are seeing a trend towards in-browser 3d experiences. The built-in 3d accelerator cards are widespread and "good enough" now in ubiquitous computing that the time is coming where Adobe will have to buy or build their own solution.
Hopefully, the next generation of "browser plugins" (like Flash) will be completely Free Software. Flash has been a nightmare, because it generally works well -- except it crashes a lot, and Adobe won't release it on "unpopular" platforms. We can't keep doing things like that, we need the web to stay open. Otherwise the web is going to become AOL 2.0, 20 years too late.
Welcome to the web. If you want users to have a consistent experience, write a desktop app.