Just can't understand why someone would pay £1000 approx
for a wheel and then save a few pounds by re using the drain plug.
Not so difficult to understand. Chose one or more:
Cycling was once a working-class sport and disposable income was tight; some of those attitudes have been carried over even now that we ride bikes that cost more than a workingman would have earned in a lifetime back in the early years of cycling. (My first Porsche cost less than my current bike...)
Many forum members are Scots. That too is a philosophical consideration.
It is probably natural for a higher percentage of cyclists to be conservationists and environmentalists than the adherence to those religions in the general population. Certain attitudes and practices follow and may be widely observed on cycling conferences and among pedal pals.
There are some practical shopping difficulties to do with Rohloff's packaging and cataloguing practices causing threshold resistance (a technical marketing term for a psychological barrier that can be created or overcome by certain pricing practices). There is for instance a single service oil kit, very uneconomical but complete down to a new Loctited drain screw; the threaded tube and syringe in it is reusable. There are also several bulk service sets, for instance one of 250ml each of cleaning and all seasons oil, enough for ten services, sold at a substantial saving. But there is no bulk pack of drain screws; you have to buy those individually, and at 250ml bulk buy level the 10 drain screws work out as expensive as 250ml of oil. Subjectively, that makes drain screws seem very expensive, well worth reusing. It's standard motivational psychology.