Is there a motivating factor for providing a reference in Germany?
My experience in the US is not necessarily that people are worried they're going to be sued, or that they couldn't make an objective reference, but that the effort and risk are both non-zero -- and the benefit to the company is ~zero.
Employers are legally required to give you a reference letter (“Zeugnis”) when you leave, and also whenever you request one or are about to take a long leave (“Zwischenzeugnis”) - I received one before I left for my year of maternity leave. Your prospective employers absolutely expect to see at least your most recent one, and I had a bit of fun explaining to the boss who hired me that all you’ll ever get out of an American employer is dates of employment and job title.
If you work here, keep up with them as carefully as you do your employment contracts.
I have colleagues who habitually request a Zwischenzeugnis every 3-5 years, even if they’re not currently looking for a new job.
The motivating factor is that the employee simply has a right to a reference when leaving.
Sometimes an employee might ask for an interim report (for example when changing departments, etc.) but that's something that is provided on a voluntarily basis.
I just researched it a bit more. So while you don't have an entitlement to a Zwischenzeugnis per se, you are entitled if you have a "good reason" to request one. According to some judgements a "good reason" is for example a change of your superiors or if you want to apply for a job elsewhere.
In my career I've requested quite a few Zwischenzeugnisse and never been denied. Probably a place where you have to fight to get one is not a place where you want to be employed anyways.
My experience in the US is not necessarily that people are worried they're going to be sued, or that they couldn't make an objective reference, but that the effort and risk are both non-zero -- and the benefit to the company is ~zero.