Good question. I'm the author of Cashier for Mollie and will continue to support it with my team. With full backing from Mollie.
Only the docs have been removed from laravel.com . Cashier for Mollie's internal mechanics are an entirely different beast, i.e. running all of the payment scheduling locally instead of depending at an external service. The Laravel core team is not completely familiar with it (it's a lot to take in) and Taylor decided not to portray it as their work. Which is totally understandable.
We're now preparing for the v2 alpha release in March/April 2021 🤞. It's launching to a closed test group at first. If you're interested you can sign up here.
Along with the launch we'll release a dedicated documentation website.
I have also visited the issue page of cashier-mollie and saw that the v2 is coming out in summer. So they are still active! And of course, when @sandervanhooft is backed by Mollie this gives me the confidence that the package won't disappear in the future time soon.