IGN still has one, humble bundle. I'm familiar with the other digital stores like fileplanet, stardock etc, they all sold limited items, as did Steam at the time. There is more then 4.... You might want to count again.

Note how it says on the western side....loot boxes were already in MMOs starting with Maple Story, this is how they payed for the free to play.... Which also came from MMOs. You didn't have to use loot boxes in TF2, you could just buy the item which funded the game and the community members who made those items. It allowed modders to move from a passion project to having a career.

Sell now fix later.... No that's not what early access is. That system which was already in use by other platforms again.... Sigh.... Was a way for players to invest in games. It allowed many huge games to fund their development like Rimworld, Factorio, Minecraft, Baulders Gate 3 etc.

I'm getting the idea you are some young kid who doesn't actually know the industry at all let alone about Valve.