I’ve had to replace two taps recently; one in the kitchen and one for the bath. On both occasions I have initially narrowed my choice down to one from either Hornbach or Obi and found out later, but fortunately not too late, that the chosen items are not Swiss standard and would not have worked in our house.
In the first instance there was a special offer from Hornbach but, on closer examination, the tap was not suitable for Swiss main water pressure hot water systems; in Germany apparantly the hot water systems are not mains pressure. In the second case, that of the replacement bath/shower mixer tap (DE: Armatur), I actually went in to Obi hunting for a specific tap I had found on their web site. I asked an assistant there to help me find it. Fortunately this guy knew his stuff and warned me that the item was a German standard item. The German standard is that the distance between the cold and hot inlets is 150mm. The Swiss standard is 153mm so near but incompatible. But there were many items in the selection there that were only German standard and it was not made clear on their web site.
There are other obvious problems with electrical appliances that have a German standard plug (SchuKo) or maybe garden plants that are unsuitable for altitudes above 300m or kitchen appliances that are 55cm wide instead of 60cm
I’ve used French and German taps in various installations, kitchens and bathrooms, without any mains pressure issues - maybe I just got lucky? - but the distance apart and indeed the threads themselves (Male vs Female and sometimes a different size) can be problematic. Adaptors are available, but can be difficult in enclosed spaces, especially if the original installation in a tiled wall is badly done, with one pipe further recessed into the wall than others (which has once lead to the adaptor being twisted and eventually cracking). They’re also not so aesthetically pleasing.
But the prices of Swiss standard ones are ridiculously higher, and with both Hornbach and Bauhaus having multiple shops in CH now I’ll be sticking with them for future installations, like the new bathroom(s) planned.
Around here we now only have one Swiss DIY chain represented (Co-op B&H now having merged with Jumbo) and neither of the shops within reasonable distance have a full range of piping/adaptors/fittings, whereas Hornbach has everything. I suspect in the future that the Swiss standards will be slowly replaced by EU norms. I’m pretty sure that the proximity of a huge Hornbach lead to the closure of our closest OBI two or three years ago, so more people will find themselves in the same situation as time goes on.
Kitchen ones, i.e. not built-in to the wall, I’ve had to fit new end fittings to anyway, as they’re an old Swiss standard, but I think the newer standard is the same (as German/EU ones).
They’ll still produce them until all the 55-width kitchens have been ripped out and replaced, but rarity and ack of demand will drive their prices up such that people will want to upgrade to fit 60-wide ones in,
The problem is that usually (I believe) you have to remodel your kitchen.
That is an expense few want to entertain (unless they want or absolutely need to) - even more so your typical landlord.
I bought my apartment with a kitchen and I like it: things are 90%+ where I want them. If I would remodel it, it would likely look more or less the same (same layout) - I’d just be down 30 grand or more…