Reply from Germany when I posted the question on their board
That's not true!
Also in German hospitals you go now over to patients to miss certain hospital clothes. In the clinics where I am a regular guest, special underwear, bathrobe and slip-resistant cloth shoes are on the surgical wards shirt, usual. Only when the patients receive rehabilitation measures, they may 'daytime' in private clothes, such as tracksuits hatch. But street clothes is prohibited.
Fundamental changes are likely in the private hygiene behavior and the textiles. Previously, the clothing made of natural fibers usually was washed at 60 ° C and was therefore "clean", today one often has artificial fibers that are washed only at 30 ° C, what bacteria is wearing nothing.
In addition, probably the German virtue "cleanliness" is no longer so common and patients probably often with filthy clothes showed up at the hospital, which is not so pleasant even for the nursing staff.
From the patient side, the new patient clothing is perceived differently. The younger generation knows them based on relevant U.S. TV series and feels it as "hygienic", the older generation has its trouble with it and perceives it as "embarrassing" and "shameful", also because it's just open back. Personally, I would - if I'm not technically restricted movement - prefer private clothes. In favorite nightgown you feel right at ease.