You can’t physically do top money day after day on semis it gets draining unless you have 4-5 upwards every time you pull up it ain’t happening,easy access big properties is where the gravy is at priced how they should be.
Why would anyone want to drive about park for 1-2 and have to be rushing about for another 1-2,saying there the jobs you want is like trying to make a silk purse out of a pig.
I think your ideas are skewed by the fact you obviously work in really nice rural southern areas where the price for all services are hiked.
What i am faced with in an ex mining town of the industrial north is a densely populated urban sprawl with 99% of properties being flats, terraced and council houses with semis and small detacheds thrown in.
In and amongst these houses and in small villages in the surrounding countryside are the larger gated properties. The problem is these larger houses still have the same pricing mentality as the smaller houses because its in the same area. Indeed a lot of people who live in these big houses grew up in the city, rich people from down south dont choose to move here, they grew up here and became successfull enough to buy a big house, but still carry the local market rates in their minds from when they lived in a smaller house. They have had window cleaners before from the same area cleaning their houses cheap and they have an idea on what the "going rate" is.
You cant get £60 for a big house in a posh street that backs onto a council estate where some vest wearing fools are charging £5 a house. Its not that simple, window cleaning prices are affected by geographical location.