I activated throttling in Firefox, setting it to "Regular 3G". I went to Youtube, selected a random video I had never watched before (so no cache): https://www.youtube.com/watch?v=6mMIOhoUcCM
It loaded for about 10 seconds then started playing at 480p. Quality was fine, it's SD but sharp. Once it started playing it wouldn't buffer anymore: https://svkt.org/~simias/up/20200819-153915_youtube.jpg
Then I went on Reddit, same settings, this page: https://www.reddit.com/r/funny/comments/ib6gmu/i_pretended_t...
Reddit ends up playing in 96p apparently (judging by the file name, DASH_96, altough maybe it's misleading). It looks like this: https://svkt.org/~simias/up/20200819-153748_redditvideo.jpg
Note that in the "optimal" version of the video the text on top is perfectly sharp.
So you can spin that any way you like, doesn't change the fact that Youtube performs vastly better in the same degraded conditions. But maybe the target demographics are people who have a fetish for ultra blurry video?