250-300 £ today are part of the average monthly salary.
Guess that, back in the seventies, they were almost the whole salary.
Firms had a higher profit on each single machine, also small firms were able to survive with small production lots.
The more a firm grows up, the more has to sell
To sell more they have to cut prices
To reduce prices they cut costs
Some moves are clever : Electrolux has no more "AEG" parts and "Zanussi" parts. These are lower logistic costs. Compare current Aeg and zanussi dishwashers : they have just different racks, sprayarms and fascia, but cycles, tub, sump, filters and i guess pumps are the same. Pity they also save on the build quality of plastic parts ....
Not a case small firms that made nice products today don't exist anymore. Often their badges are now used by big corprations