Comment by hadlock

The barrier to entry to compete with steam is a newspaper ad, a CD-R writer (or usb stick) an envelope and a stamp. There are a million ways to deliver software. You can setup a website as a front to an S3 bucket and then just pay per download of the file. You have epic, origin gog, greenman gaming etc they all exist, but people choose to buy their games on steam, and publishers choose to sell their games there despite the 30% cut. I wouldn't call it "locking up", they just provide a Better Service to customers.

The last game I bought that wasn't on steam was probably Kerbal Space Program, in ~2014, and later converted my key to Steam when the option presented itself.

*Epic offers 0% cut for the first year to most indie games