There is a broad alliance of patent holders behind h.264 and even broader behind HEVC. The difference that HEVC made was including HW and SW partners, so that it could be designed for easier processing using combinations of CPU/GPU. Also, the design goal was to produce a codec @ half of h.264 bitrate - this was close, though not quite there last time I checked a couple of months ago (while the reference codec was in Working Draft 6).
As for UHD content, there are suddenly large swaths of similarly textured areas in each frame (imagine a DSLR shot of someone's peachy complexion) - all the more suitable for larger quadtree-style macroblocks. The large resolution also calls for finer motion-estimation, which is responsible for a lion's share of the encoding complexity increase - actual "compression" in HEVC has been pretty much ported from h.264/avc, and this also means that developing solutions for h.265 is going to be that little bit easier.
For people unfamiliar with the process, a compression standard pretty much describes the format of a data stream - and leaves the actual implementation to the market. HEVC working group was actually kind enough to also provide a reference encoder/decoder software, modifications of which made its way into many scholarly papers and dozens computer science students' graduation theses.
The sad truth about free codecs is that the basic technology for video compression hasn't changed significantly since mpeg2 - and the elements in that are very much patented. VP8/9/10.... won't be any different.