I think that this is really a genre question: the more tightly restricted a genre becomes, the more pieces written in that genre come to resemble one another. This could be Viennese minuets, San Francisco psychedelia or current pop songs. The first example in the video is of exactly the same chord progression used by Marvin Gaye and Ed Sheeran over which different melodies and lyrics are heard. What we have now is a kind of industrial songwriting process vaguely similar to the process of making sausages or hot dogs. The process is similar and the end result is similar. This is actually a plus because in the pop environment the listeners tend to like stuff similar to other stuff they like, so the more homogenous the product, the more likely it will be accepted. On the other hand, the danger is always present that too much homogeneity will cause boredom and rejection. You want to give the listeners exactly what they expect, with a little spice of difference.
But then you get critics, like these guys, or me, saying "hey, you're just regurgitating what has already been done." Hilariously, there was a critic back in the 16th century, if I recall correctly, who was claiming that all the contrapuntal ideas and combinations had already been tried. Two hundred years before Bach! And then Shostakovich, in the 1950s, proved all over again that even in the genre of keyboard fugues, you could still come up with lots of new ideas. (Domenico Scarlatti managed to write 555 sonatas for harpsichord between 2 and 6 minutes in length without ever repeating himself.)
Creativity is a very remarkable thing because someone can come along, and with one tiny change, or a whole bunch of them, or one or more big changes, they can transform a whole genre, create a new mood or perspective and thereby renew a whole area of music. DuFay did it in the 15th century, Monteverdi did it in the 16th century, Bach did it in the 17th century, Haydn did it in the 18th century, Chopin did it in the 19th century, Stravinsky did it in the 20th century and so on.
And at the same time, every one of these composers used a whole lot of traditional material, they just transformed it without throwing it away.
For an envoi, here is the ballade by Guillaume DuFay, "Se la face ay pale."