I feel like it only became rampant in recent years. As a 90s kid no one cared about the card packs. We all assumed they'd be junk cards and a waste of $7 or whatever. No, the move for card people back then was to wait for the card show and just buy the cards you actually want from a card dealer.
The thing is now people are marketing the pack opening. You have social media accounts of them pulling cards from packs and getting all hyped up about it. Again no one thought that was fun in the 90s, everyone hated that aspect of cards in the 90s but thats because the unboxing as an experience wasn't marketed by anyone at all. People just wanted cards they thought were personally cool in some way.
And likewise expansion of markets in the internet era means people start to have shared values of what is a valuable card based on market price vs just being interested in some certain cards out of your own interest.