You pay less because you get less. I'm selling a product. The last thing I'm going to cheap out in is sales. I'm not going to see great sales from the EGS because A)Nobody uses it

That's exactly it, Devs have to accept Steam's cut because it's essentially the only place you can sell things. It makes logical sense, but do you not see why this is a disadvantageous position for the Devs to be put in?

It's like trying to sell your hand made Combs. The gas station on the corner is happy to take only 20% of the profit. They're all over the place and accessible. But you really want to sell it at the boutique shops because they have more comb-seeking customers.

This would be a fine analogy, if there weren't a single digit amount of storefronts. Steam and EGS are more equivalent to supermarkets. Sure the odd person is going to go to speciality stores on occasion, but the vast majority of sales are done through supermarkets. Steam is a supermarket competing against speciality stores. The only other real supermarket in town is EGS and as you've discussed, it's such a dumpster fire no one shops there.

I'm not disagreeing that Steam deserves its position, it does for sure. But we live in a world where it has no meaningful competition, and one of the ways it exercises its position is by maintaining their 30% cut. A cut which was established by stores that had to manage the logistics for real physical copies of the games.

My point is that there isn't a reason that Steam has such a high cut, other than it wants more money, and has the market saturation to command more money