My personal opinion about this is that in every traditional culture dating back to many 100 or 1000 years it is a common and totally obvious thing to take the tunes of predecessors and using them. It is a kind of strenghtening the culture. And every culture after a point reach a state when you can't create anything new. Or only with difficulties. And the culture fixates itself, there will be songs sung from generation to generation, that people ask for from musicians. This is how human culture works. This is bad businesswise but if you focus on the business side too much, it will result in what you see in the world today that it will be more and more difficult to create outstanding hits, there will be a debate about copyrights at every corner, the music will become boring, because all the good tunes have been created, and everything new is just lower grade, because others have already maxed out the possibilities of the genre.
Exploiting the work of others in bad faith is a legit issue but doing that in good faith is also a legit thing, but the copyright laws recently exclude the latter.
By the way, I checked only the 1 comparison of the second video, music theory wise, the lines can be identical, but for regular listeners it will not be obvious, and that thing alone can justify to use of the tune again. I have been playing guitar for 25 years but wouldn't have noticed myself either only by listening.
Personally i like when bands use the older material of others, if they do it in good faith, the reuse originating from a fascination of one artists towards the other. Zaiko is doing that with their own materials all the time and it is a good thing, but you can hear bands doing it with each others material as well. Compare the song of Extra Musica: Lolango and Wenge Musica: Cresois. I am quite sure Roga Roga was inspired by Wenge when they wrote that song. Very similar tunes. Is this bad? No. I love it. Cresois is a good tune, and instead of some easy to forget tunes by bands recently, if they wrote a new "Cresios", I would love it.
There is a proverb: 'why changing things that already work well'
