Let me explain. We have a perfectly fine FOSS H264 codec, called x264. It is FOSS and it is superior to any closed-source offering at this time.
The issue is that the H264 spec is patent-encumbered. This means that as soon as you touch the FOSS x264 codec, you leave yourself at the mercy of the MPEGLA consortium and their licensing terms.
Right now they are offering you a big, nice carrot: you don't need to pay for fewer than 10K views. You feel safe because you don't believe anything you encode will ever reach 10K views and the H264 codec is pretty good - quite tasty a carrot, isn't it?
However, you forget that the MPEGLA (Microsoft, Apple, ...) can change their licensing terms at any point. It is they, not you, who are in control. Today it's free but tomorrow it won't be - you can bet your ass on it.
We've seen this happen with GIF. We've seen this happen with MP3. And the sheep are flocking to H264 now.
But this time, we actually have a chance to fight back with VP8.