UK: Punitive property taxes on hangars, briefing rooms, etc.
US: State subsidised airfields
UK: Weather allowing VFR flying ~250 days per year
US: Weather allowing VFR flying ~350 days per year (in much of the continental US if not all)
(Assuming that fixed running costs around about 50% of the cost of running an aeroplane, that's just added about 15% to the cost of running an aeroplane.)
UK: Fuel £1.30/litre
US: Fuel ~$4/gallon (about £0.52/gal)
(So at 30 litres/hr of a typical 4-seat aeroplane, that's worth £23/hr difference)
UK: Aircraft parts mostly imported from US
US: Aircraft parts mostly made locally
(Add 17.5% import duty to the parts, plus cost of shipping - I'd guesstimate that's just added around 4% to the cost of running your aeroplane.)
UK: Ever shrinking military
US: Large military turning large numbers of skilled people out into the labour market without their having to pay their own training costs.
(Hard to quantify, but it must have an effect)
UK: Typically 25-30 days paid leave per year
US: Typically 10 days paid leave per year.
(So, assuming a similar working week, that's added 8% to your labour costs with nothing else accounted for)
UK: CAA required to charge for everything
US: FAA paid for from central taxation.
(Ever looked at the CAA scale of charges for licences, tests, flying instructor revalidations, AOC inspections, airfield licence renewals... All of this ends up on your flying bill. On the other hand, in the USA they must be paying it, it's just invisible.)
Plus the cost of living is rather higher in the UK, so people (FIs, mechanics, engineers, cleaners, the lot) all have to be paid more in the UK to live.
None of which is about company profits I'm afraid, which I think are fairly similar both sides of the pond - possibly slightly better in the USA. But does, IMHO, explain why flying is so much more expensive over here than over there.
That said, those of us who buy shares in aeroplanes in the UK, and don't mind doing a bit of aeroplane cleaning and maintenance ourselves aren't paying that much more than renting in the US. I fly a very nice 4 seat taildragger for around £65/hr over here - including my monthlies; and I'm sure that I'm not unusual in that- I know of several C152 (or similar) syndicates where around £45/hr would be about right if you flew 3+ hours per month.
So, I think it's a combination of taxation, fuel company profiteering, weather, employment culture and geography. I really wouldn't blame the FTOs for much of it.
G