Well, of course a ticket, that was limited to three months did not have a lasting effect on car usage. No one would sell their car and switch to public transport because of such a short, temporary price reduction. Even the follow up ticket (costing 49€ currently) is only guaranteed for a year at a time, then the government has to discuss funding again with the federal states. To have people switch from cars completely, it has to be a long term alternative.

But even if only some trips are now done with public transport instead of car, it is still an improvement.

I agree with you, that a good quality is also important, but I don't think it will happen, if the financing for improving the quality has to be primarily via ticket pricing.