gitlab and bitbucket aren't as good, I've tried them and more.
GitHub isn't a commodity that excels only because of it happening to be popular. People choose GitHub because it's both popular and good. It has competition, some of which are better for specific circumstances, but as a whole they don't execute as well.
Let me contrast with Facebook – it was only good, in my opinion, for a brief period starting in 2005 which happened to coincide with my freshman year of university. As it grew and changed, I found myself and very many of my peers hating each significant change. The only reason I've kept an account is because it's popular – it stores some weak social connections which would be otherwise lost.
Horses for courses. Plenty of people prefer those other providers, just like plenty of people prefer one brand of toothpaste over another. Toothpaste is still a commodity product.
I've never used gitlab, but I find bitbucket to be identical to github in every way that matters.
And bitbucket has unlimited private repos for free compared to github's limited number for a fee. I moved my lab repos to bitbucket when we outgrew 10 private repos. It was going to be quite expensive to add more at GitHub.
(Most of out repos are public but some things you want to keep private at first.)
Bitbucket is not as good? Feature-wise they're almost identical.... I use github for my FOSS projects and bitbucket for stuff that shouldn't be public, like for-profit soft and side-projects. If you don't see added value in free unlimited private repos that's not the case for many of us.
I like Github best, but will readily admit it's mostly just because I'm most used to it. Like you I use both, with Bitbucket for my private stuff and Github for the public stuff. The latter mostly because that's where people are.
I gladly pay for the Medium plan just for my own personal private usage. It's a wonder these services last as long as they do, when you guys don't want to support them.
The point is the nature of git means I don't really need any of them. They're convenient as a public dumping ground (Github) or "backup" (Bitbucket) with a decent web ui, but if they disappeared it'd make very little practical difference for me (other than recruiters having to find me via another site).
GitHub isn't a commodity that excels only because of it happening to be popular. People choose GitHub because it's both popular and good. It has competition, some of which are better for specific circumstances, but as a whole they don't execute as well.
Let me contrast with Facebook – it was only good, in my opinion, for a brief period starting in 2005 which happened to coincide with my freshman year of university. As it grew and changed, I found myself and very many of my peers hating each significant change. The only reason I've kept an account is because it's popular – it stores some weak social connections which would be otherwise lost.