Television sets are the extreme example of what’s possible. I don’t see any other product where they let the price collapse like that. Do you?
Discussion
Everything (save for artificial intervention) is getting cheaper, starting from commodities. This is true when measured with a constantly shrinking measuring stick in fiat.
Now couple with technological progress and you will see why the price of un/low regulated products keeps dropping. 
Why aren’t my Mac upgrades cheaper than before? Why aren’t iPhones getting cheaper? Why aren’t my cars getting cheaper? Like televisions.
All of the above: you are measuring in fiat (imagine measuring your nephew’s growth with a height measuring stick that changes its length materially in months).
Macs & iPhones: you are conflating luxury goods with cost of unit compute power.
Cars: regulations. See https://www.roadandtrack.com/reviews/a45752401/toyotas-10000-future-pickup-truck-is-basic-transportation-perfection/
Modern TV sets are data harvesting computers with big screens and producers make a lot of money selling the data they harvested from you. Some make lore money from selling your data than from the hardware itself, they decrease their profit margins on the hardware to sell more TVs to harvest more data which is more valuable.
https://www.theverge.com/2021/11/10/22773073/vizio-acr-advertising-inscape-data-privacy-q3-2021