I love threads like these, very inspiring. The tape on the passports is smart! I'm always worrying about taking the wrong one. Sadly the tip is a few years late now that everyone minds their own haha.
I sort off don't understand coverless duvets because that's the way it used to be, albeit with a sheet underneath. Granted, I understand that the new kind is very easy to wash, so that does make a difference. Duvet covers were invented to make bedmaking easier. Shaking out top sheets and folding them was fiddly. But I'm not starting a war on it, each to their own. I get why you'd use a top sheet and a duvet cover to make the cover last longer before going in the wash maybe, but I do kind of feel you're fooling yourself a little bit. No skin off my nose though.
I give you the Ikea catalogue from 1972, sporting only "duvets" (blankets is a better term) and top sheets. https://ikeacatalogues.ikea.com/77436/1102671/pages/1e8b4f3e-3bed-4ebe-a02f-5c81eca3b06b-at800.jpg
The very next year it's all about the new-fangled duvet covers!
https://ikeacatalogues.ikea.com/77436/1102673/pages/92a084d7-e432-44ea-ae5a-d4dc1126c489-at800.jpg
Text (freely translated):
For a long time duvet covers could only be seen as a continental bedding luxury, a different kind of bedding culture that made us think of delightful holidays.
Comfortable and hygienic, but unthinkable for us Swedes.
Luckily however the duvet covers have arrived. Colourful and pretty they give us as much textile in our home decor as blankets! Easier to make the bed, easier to launder.
You put the blanket inside the "sheet bag" and use a bottom sheet in the normal way. Practical at home, and practical if you're staying overnight and borrowing a blanket. Duvet covers are mostly mangle free. The blanket remains fresh.
The most modern duvet covers, like Ikea's, are stimulating home decor accents. [...] A new way of making the bed! More colour and a more comfortable everyday life!