It’s hard to overstate the psychology behind the github profile. As a developer, your github profile shows that you’re actively developing, whether it’s for open source projects or for work projects. My previously company used a private gitlab install, which meant only my open source work showed up on github. My current company uses github, which means my profile shows green all the time.
We’re a small company, but the github costs are a drop in the bucket. As others have said, it’d take something truly federated, or a crazy price jump from Github, for me to consider moving. It’s free for my open source projects, it’s a small amount for my company, and I have a public profile I can point to whenever I’m discussing my development.
They’re so insistent on getting people to do their Subscribe & Save stuff, with lots of discounts for making a subscription. And I take the discount and cancel the subscription as soon as it shows up. The entire point seems to be to get people to subscribe at the low price, and then jack the price up, sometimes double, when it starts recurring.