Have you ever tried to setup a development environment in Windows? Windows fucking sucks for development unless you're committed to handing over wads of cash for a VS license, and even then it's really only good if your okay using a bunch of proprietary MS stuff.
Darkaga
Storage and bandwidth definitely weren't cheap in 2003. Additionally Steam provides features that a brick and mortar store could never even think of providing, including updates, DRM, instant access to global consumers, community features, in-depth data analytics, and the ability to adjust pricing in real time.
While a lot of the work Valve has put in Steam seems both obvious and ubiquitous today, these were features they pioneered for both developers and consumers.
I'd also like to point out that the only digital marketplace I'm aware of that charges less than 30% by default (Epic) is famous for losing billions of dollars in the endeavor.
Before steam, digital sales of games wasn't really a thing outside of a few niche examples. The 30% cut was the same percentage that retail stores were taking.
More like low below (the surface)
Slipknot is not where I saw this thread going but I'm here for it.
I did a few years in a Security Architecture role at a large enterprise. The amount of times I had to explain basic stuff to Enterprise Architects, Principal Engineers, and Principal developers with decades of experience was truly mind numbing.
It would need to be $1.05 now.