Sorry what? It seems the article author knows nothing about Github. Not a unicorn and only took investor money after being profitable for a long time.
Yes the cost is going up for many people. No, my company doesn't plan on moving anything off of Github. It's well worth the cost.
If it were to get more expensive I could probably use self-hosted GitLab however.
That being said I'm pretty sure that some will be unhappy with the change. As andraz mentioned in another comment - moat gives leverage. But even though I'm pretty sure GitHub is fairly elastic in terms of pricing with large enough companies (with large enough probably still being not that large), I find it hard to believe that their bottom line suffers. This means that customers are picking up the tab and as silly as this article is, prices did go up and some people should migrate.
Naturally this opens up space for competition which will figure out how to take a bite here and there. But that will take quite some years.