Yes, I was there. I sat through a presentation about their original concept for selling content in Team Fortress. Trust me when I say that it turned out nothing like they originally conceived of-- which is a whole different story. The whole idea that they "invented" loot crates is weird because the idea goes back to collectable card games and other things. I am not saying they are without fault.

You could also argue loot crates are just the digital version of Pokémon card packs

That is not true. Gachapon mechanics existed long before, valve only took it to western market, not knowing the consequences. Remember this is way before gambling sites. It was a way to earn a cool random hat on TF2.