So people being able to buy steam keys cheaper than from Steam doesn't prove that games can be bought cheaper than on Steam? What?

And even Valve says

It's OK to run a discount for Steam Keys on different stores at different times as long as you plan to give a comparable offer to Steam customers within a reasonable amount of time.

https://partner.steamgames.com/doc/features/keys

Comparable not same. Which provides a lot of flexibility on discounts outside the steam store. And isthereanydeals data that tracks all the prices over the years showing that your claims don't match the reality of steam keys not going on sale cheaper than on Steam sales.

But, you seem to live in your own reality so we are just arguing in circles. You ignoring real sales prices and just fixating on some imaginary price outcomes where Steam key sales prices aren't cheaper than Steam sales.