Youtube does transcode to H.264 (which is the format which requires licensing, x264 is an open source encoder that outputs H.264 encoded video). There are a variety of chrome extensions and similar which will allow you to select H.264 on the majority of Youtube videos if you so choose, much of youtube's content is available in h264 as well as other formats.

Second, the reason that they default to VP9 is because it is a better low-bandwidth experience. It's certainly a tradeoff against power usage with H.264 since hardware acceleration for H.264 decoding is often available, but it is a calculated tradeoff based on the fact that people want their videos to load faster and in higher quality. You can read a little bit more about that here. https://youtube-eng.googleblog.com/2015/04/vp9-faster-better...