Right now Humankind is sitting at $59.99 USD ($49.79 after discount) but this is the Deluxe Edition.

My question is, will the base game be $50 on release after the Deluxe goes back up to $60?

The reason I ask, it would be worth buying this deluxe edition if the base game is just going to be the same price on launch as the preorder is now. BUT the contents are not really worth it if the base game will be $40, which some games are $10-20 less than their deluxe counterparts. Avatars and profile decorations are hardly worth pennies to me. The only worthy thing to purchase in this 'deluxe' edition would be that DLC pack which at least comes with game content.

Until I know for sure, I think I will preorder the game just before it launches and see the price after. You can always return the game and repurchase if the price is substantially lower. Otherwise, it would be a deal to preorder as your getting that DLC for the same price.

Would love to know for certain though.

Pretty sure the discount is one of the bonuses of the Deluxe, and the base price will be the same

From the Stadia page

"£39.83[$55.22] is a special pre-order price and will go up to £47.99[$66.54] at launch (Or local equivalent)"

Dunno why the cost is in pounds considering neither I or Amplitude are British. I can only assume the listed dollar cost being different from the equivalent pound sterling is just a regional pricing thing.