The market segment of web hosted Git repositories was a relatively new and small market segment when GitHub got started back in 2008.
GitLab didn't appear until 2011, and at the time it didn't feel to me like a direct competitor. So GitHub had quite a bit of extra time to establish its presence and capture a large share of a growing market.
For a large chunk of GitHub's users, GitHub fulfills their needs well enough that they don't feel much motivation to make a change. Even if GitLab is better than GitHub for a person or company, it has to be better enough to be worth the pain of switching.
And I think for most users, that just isn't the case. Speaking anecdotally, there are some things about GitLab I like more than GitHub. And if I were starting out, I'd likely pick GitLab. But all of my code is on GitHub, and although I pay a monthly fee for private repos, it's small enough that it doesn't bother me.
What GitHub has that GitLab didn't offer in my experience last year is a snappy website. Apart from that I'm a huge fan of GitLab, it is superior.
I believe that GitHub is more popular mainly because it was first, gained traction and became synonymous for some people with git itself, and open source.
The market segment of web hosted Git repositories was a relatively new and small market segment when GitHub got started back in 2008.
GitLab didn't appear until 2011, and at the time it didn't feel to me like a direct competitor. So GitHub had quite a bit of extra time to establish its presence and capture a large share of a growing market.
For a large chunk of GitHub's users, GitHub fulfills their needs well enough that they don't feel much motivation to make a change. Even if GitLab is better than GitHub for a person or company, it has to be better enough to be worth the pain of switching.
And I think for most users, that just isn't the case. Speaking anecdotally, there are some things about GitLab I like more than GitHub. And if I were starting out, I'd likely pick GitLab. But all of my code is on GitHub, and although I pay a monthly fee for private repos, it's small enough that it doesn't bother me.