WebGL has been around for a few years now and, while support in browsers is basically universal at this point, there aren't that many apps out there making use of the hardware accelerated graphics API.
That's partially because there are still problems and not all computers can run WebGL smoothly or at all, but also perhaps because developers aren't used to this much power on a website.
Whatever the case, Google isn't standing still and has now enabled WebGL by default in the latest Chrome 30 beta release for Android. You can see it in action for yourself by checking out some of the demos here, if your device is supported.
Google has been testing WebGL in Chrome for Android for a while now, hidden behind a flag. The reason why it took so long is that hardware accelerated graphics are tricky.
Like on the desktop, the problem is getting apps to run smoothly and stably on the myriad of mobile GPUs out there. In fact, WebGL in Chrome for Android is only enabled on high-end devices with powerful GPUs.
Understandably, Google mentions the Nexus 4 and the Nexus 7, but the Galaxy S4, HTC One and similar devices should work. Last year's high-end models, i.e. the Galaxy S3 or the One X may work too. But it's not enabled on the older 2012 Nexus 7, powered by a Tegra 3 SoC with Nvidia graphics, for example.