You seem almost surprised. Since the late 1880's many a scandinavian talent has operated in many fields.
Aalto,(architecture,furniture, glass)Jacobsen (architecture, lighting, furniture, glass, cutlery), Wirkkala(furniture, glass, cutlery), Sarpaneva (furniture, glass, cutlery, silver-ware, ceramics, kitchen-ware), Saarinen (architecture,furniture), the modernist scandinavians, seem to have had an all-encompassing approach, rather than operating on a basis of job-demarcation.
It should be noted that, the major discipline to emerge was that of industrial design. Though there had been several individual talents, Dresser, Behrens, arguably it is in the aftermath of the Bauhaus, and particularly in the 1950's, that industrial design came to the fore.
The movement of former bauhaus teachers to America, and the continuing
global interest in Scandinavian architecture and design, created the conditions in which design schools flourished.
Only after the war did British architecture become a building only discipline, before that, one found the likes of Alfred Waterhouse, designing everything for the Refuge Building, Manchester, the doors, handles, book-cases, etc, rather than using a list of what the various suppliers have to offer. Like-wise Edgar Wood, really the first Modernist architect, designed everything for his buildings, whether that was in Manchester, Stafford, (arguably the first modernist house, predating anything built in mainland Europe, before the First World War(1908)) and Frinton.
Architects used to be considered as the masters of all trades. That that remains true in Northern and central Europe, is a reflection, IMHO, of just how impoverished the profession has become in the west.