Well over a long enough timeline, the need for transcoding has gone down. When media streaming was first making the rounds, every server had to transcode for the clients, like back when Xbox Media Center was actually run on original Xbox hardware with hacked setups. During that time, any media over 480p generally had to be transcoded. You used to need transcoding for anything in MKV containers, then codec of x264, then x265. Then as time went on, clients became more capable and now you really don't see a need for video transcoding of 1080p even with x265.
Of course new media formats and resolution always push against this, but then after it becomes more mainstream, the clients will adapt. As you said, right now the bleeding edge push is 4K and 8K media with HEVC. The encoder for HEVC is insanely slow, so I don't see it proliferating until the encoding times are addressed.