So the "Classic" Tomb Raider games were released on Steam recently...

Revelation + Chronicles are 20 Euro....while on GOG they are 10 Bucks...

But the biggest whopper is the original trilogy, which is 30 Fucking Euro on steam while they are 10 Dollars on GOG

A quick reminder that 30 Euro is roughly 39 Dollars, so in essence, you are paying 400% more on steam for the Original trilogy than if you buy it on GOG. This is also adding the fact that the versions on steam come without any extras whatsoever.

Can someone please explain to me what is going through Square Enix's fat head right now?

Steam price games with sales in mind. High initial price to allow a higher discount later on and make people think they are getting a better deal than they are.
Happens in all aspects of retail all the time.
Why GOG is one of the best.