YouTube's a video encoding site. The original video that was given to YouTube will have been substantially larger than 13 kb-ish.
If your content is audio only then use an audio encoding site like SoundCloud. Or, if you really want to use YouTube, then you need to get them to develop an audio specific option.
I think we already have tons of brilliant people developing video codec. I'm sure they are all well aware there isn't a way to define part(s) of a video a slide show. What is missing is people pointing out how silly this is. The keyframes also define the seek points. Its a mess.
Yes, the formats and players should be changed to also allow more seek points than the key frames, exactly for these "picture not changing" scenarios but with the audio content we want to seek and consume.
And then additionally, there should be better recognition of the "picture not changing" conditions, to allow better use of such a feature.
If your content is audio only then use an audio encoding site like SoundCloud. Or, if you really want to use YouTube, then you need to get them to develop an audio specific option.