I think they just get them from the same supplier as the German Aldi stores where they are sold during the Oktoberfest season. So it's not a Swiss thing.
It's culturally speaking Bavarian, which means two third of today's Bavaria, Austria and Südtirol/Alto Adige. The wester frontier in the Swabian Alps is hard to determine but it's not culturally alemanic so it might be only the eastern fringe of Württemberg (Eastern side of the Swabian Alps only). One finds them however in Trachten north of the Bavarian frontier because of contacts of influence of whatever. South Hessen would have them too in music or traditional dance groups, although they are culturally Franconian. In Northern Germany, they are totally absent. I've always wondered if the expansion outside of the Bavarian core region is recent or older. I've never bothered researching the topic in the library, sorry.
But I am quite sure that they are traditional also in parts of east-Switzerland (Appenzell and perhaps a bit more in that corner).
EDIT : I've found it, it's only known in Switzerland as the yellow Sennentracht in Appenzell.
Yes, although the stuff being marketed by Aldi is mainly focused on a limited-time Bavarian products theme, similar traditional clothes are worn by folks in central Switzerland (at the very least) at special regional/social/traditional events.
On the German side, Lederhosen are a traditional dress in Altbayern, which is the Federal State of Bavaria net of Franken and Swabia (i.e. the western part from Augsburg to Allgäu). Unfortunately, the Lederhosen-and-Dirndl thing has spread to other traditional festivals outside of Bavaria, like the Cannstatter Wasen in Stuttgart in recent years.
This is indeed recent and purely commercialization of the event. I've seen it happen in the last 10 years. It shifted ca. five years ago with a quite aggressive marketing of the event, trying to make it as successful as the München one. Nothing traditional there.
Lederhosen and Dirndls really are worn as everyday clothes in Bavaria. In Munich, where I once lived, I'd often see people wearing these clothes while they were out shopping. I got told that these were mostly country people coming to the big city, but I saw one or two people wear lederhosen at the big company where I worked.
Of course there are loads of people wearing Trachten at the Oktoberfest and Frühlingsfest, but often (for the Bavarians who went) they'd be the clothes they got bought as a rite of passage, and had had for years.
I have 4 dirndls, I think . But mom is Austrian and we lived in the Munich area and I got into it! During the Wies'n, those weeks of Oktoberfest, all of Munich turns into people wesring lederhosen and dirndls. Otherwise, you don't see it that much on a regular basis, although still not out of place for those who wear them.
When I am in Salzburg I drool over the gorgeous expensive ensembles in the windows - costing 2k €...maye some day I will buy a nice one...but it is so hard to choose and tbh, there really aren't a lot of occasions to wear them!
To chuck in my two Rappen, that what people call Bavarian Tracht these days is actually from Miesbach, near Bad Tölz and called "Miesbacher Tracht" a very local Tracht and only exists since 1900. Although there were other Trachten, non have been documented, designed to last a lifetime they started out as pure work clothes, in the sense that Jeans started out as tough working clothes.
By the way the original "Krachlederne" as they are also known as are made from Hirschleder or deer leather and if you buy one of these things from Aldi, remember, they are an embarrassment, pretty please don't wear them to go to the Octoberfest.