The term 'transmission line theory' (or even 'transmission' for that matter) doesn't appear to have been mentioned in the video at all[0], and this is a complaint that was also raised by Dave Jones[1] in his critique of sorts. The video is fundamentally about transmission line problems and the term is mentioned both in the description and the word document containing further analysis, but its omission does lend some credibility to the complaints in the parent comments that the video style is intentionally pedantic (it is a pure physics vs practical electrical engineering take after all) and presented as a controversy which comes off as a bit shallow as a result.
If one were to put on a tinfoil hat it doesn't seem like much of a stretch to imagine that the plan was to have a follow up video to settle the controversy with the gist of the video being about transmission line theory and concluding with a practical demonstration of the effect.
[0] I don't have the time to carefully watch a 15 minute video to verify this, and demonstrating a lack of evidence seems difficult, but the subtitles for the video can easily be downloaded with youtube-dl and then grepped or opened with a regular text editor. Note that these subtitles are manually written and not auto-generated by youtube, and while it's possible there's some differences in the script and what is said it seems unlikely.
If one were to put on a tinfoil hat it doesn't seem like much of a stretch to imagine that the plan was to have a follow up video to settle the controversy with the gist of the video being about transmission line theory and concluding with a practical demonstration of the effect.
[0] I don't have the time to carefully watch a 15 minute video to verify this, and demonstrating a lack of evidence seems difficult, but the subtitles for the video can easily be downloaded with youtube-dl and then grepped or opened with a regular text editor. Note that these subtitles are manually written and not auto-generated by youtube, and while it's possible there's some differences in the script and what is said it seems unlikely.
youtube-dl --write-sub --sub-lang en --skip-download https://www.youtube.com/watch?v=bHIhgxav9LY
grep -i 'transmission' 'The Big Misconception About Electricity-bHIhgxav9LY.en.vtt'
[1] https://youtu.be/VQsoG45Y_00?t=1013 (16:53)