As with many things time changes expectation. People used to see kit cars as a cheap hobby, nothing is cheap now and people do not expect it to be,
You are correct the expense of a Westfield now is much higher but there are reasons for that. Legislation, Labour, materials, buildings, energy costs have all shot up but that is the same for all manufacturers, but quality also. When I looked at the cost of the newest demonstrator from AK for the GT40 it was £180k !!
Robin Hood was the cheapest you could buy even a Dutton was more expensive but now the GBS, that was RH is knocking up in price when you add it in.
However you can buy a used Westfield for a fraction of the cost of a new one and will get as much fun as driving the latest. For many a full build is daunting but restoring or modifying a used one is easier and cheaper.
It is horses for courses. With the Caterham it is a bit like VW campers, you pay a scene tax to be part of the group, is a Caterham better, no just different