It's a web scraping tool that requires constant daily maintenance. I don't think they get enough third party contributors to justify keeping it open source. I bet most users are just there to raise issues whenever something breaks.

Looking at the git history they did get decent amount of contributions

they are of course completely free todo this but it does feel a little like profit from OSS and take it private once you have enough

They're not "of course completely free todo this" unless they have permission or copyright transfer from every single contributor. They don't solely own full copyright to the combined product, they have been licensed these contributions under GPL, if they want to distribute the combined product (their own code + contributions) they either have to follow the licence conditions or it's a copyright violation.