I think it’s fucked up that the federal government introduces a policy and then tells the states “you figure it out”, indeed.

But I think it would be reasonable to add a time commitment to the ticket that will allow enough revenue to be collected after the period of intensive use (referring to the line in the German article: “Die Option zur monatlichen Kündbarkeit werde intensiver als erwartet genutzt. Das nimmt den Verkehrsunternehmen Planungssicherheit.”) The Probe BahnCard still has a minimum running period of 3 months, so making D-Ticket’s running period at least three months would be understandable. I can’t say if that will be enough to keep the pricetag of 49 Euro even remotely sustainable of course.