Demise of the Radio & TV Trade.

[Murphyv310]

You also need to factor in the large population increase in Kilmarnock and the other big towns, the road network to Glasgow is now all motorway so many have moved here. The town though has lost many industries.
EG. BMK, Massey Ferguson's, Saxone, Glacier Metal, Johnnie walker, to name a few. Out with the town, SKF, Scottish Aviation etcetera.