I'm also a big fan!
> The ticket can be bought only throughout the summer months.
The ticket is a new thing, by the way. The reason it's only available in "summer months" is because they haven't finished thinking about how it's gonna be after that.
However the transport companies already manifested interest in continuing with the ticket for €69 [1]. Sure, not €9 but still progress. Some parties recently suggested €365 per year. Both are still a great price IMO considering I used to pay €40 a month (€63 in total, my company pays the rest), for a ticket that only covered Berlin!
[1] https://www.tagesschau.de/wirtschaft/verbraucher/69-euro-tic...
[2] https://www.iamexpat.de/expat-info/german-expat-news/left-ca...