2-3 hours?
It will take at least that long to run a full virus scan on most older kit.
I assume that the geek will have an investment in infrastructure such as a home office with fast broadband and all the latest Windows Updates held locally. Also insurance cover.
Working at the customer's home is a recipe for trouble as a lot of the work will be starting a job then waiting for 2-3 hours to finish and any downloads will be constrained by the customer's link speed.
As already stated upstream it is hard to justify paying a decent price to cover several hours of skilled labour when the capital cost of the hardware is around £300. Back in the day when a decent PC could cost £2,000 paying
£200 to fix it looked reasonable. Try charging that today.
This also explains why small businesses tend to use low skilled support because the cost looks unreasonable when you have bought a couple of XP machines 10 years ago and can't move because your business specific software package won't run on W7 or W8. The perception is that if the suport costs more than a new machine then it isn't good value. At the price point they are comfortable with they can't afford marketable skills.
Seen that with a local business I know.
So who are these geeks who can offer a quality service at a low price?
Retired and bored ex-IT professionals who are time rich but cash poor?