In general, while I agree with much of Beato’s argument (’technical’ perfection and ease of use vs. skill, inspiration and ’selection’), I also think there is a lot of survivor bias whenever one is comparing ’the great music of the past’ to the ’poor music of the present’. A lot of past stuff has rightly been consigned to the bin of history.
The arc of music like literature, art, and architecture has been bending upward since the dawn of time, so I don’t understand the premise of the video.
I’m not sure I understand what you mean (i.e. ’things have always got better since the beginning of time’ or ’things have got better on average over time’), but either way I disagree with it. Bach is pretty old, and Hildegard von Bingen is even older, but they didn’t write bad music; neither is ’worse’ than anything - and I mean anything - written today. At best, it’s incomparable. Just like at best Damien Hirst and Mark Rothko are incomparable to Vermeer and Piero della Francesca. At best.
Engineering to some extent has been progressing, but architecture hasn’t necessarily "progressed" - Hagia Sophia is an architectural masterpiece, as is the Pantheon, as are Palladio’s villas. Not much designed today is ’better’ - even if it is bigger and has more functionality (not least because we can provide more functionality).
The Mahabharata; Greek myth written down by ’Homer’ (or many Homer); Aristophanes; Cicero, Livy, Caesar and Martial; the Edda; Dante; Shakespeare - all on an ascending arc to ’Butter’ by Asako Yuzuki (no offense meant; current bestseller at Waterstones UK).
Or did I misunderstand your point?