You're right, I checked, there were pre-orders, which made zero sense given there was no promotional offer of any kind and very little demand then.

Anyway the Pixel 3 and 4 were pretty big flops. Pricey and uninteresting devices, with abysmal battery life for the non-XL variants. I remember third party sellers fire-selling their stock of Pixel 3s during summer 2019.

The 5 and the 6 are priced a lot more reasonably, Google probably doesn't need to do anything to sell their current stock, so if you believe you'll get better than $200 headphones, good luck with that.