As an ex Kingston resident whose otherwise always lived in Leeds I can say that the potential to sort London out using public transport is at least there. On Tuesday night I went to a retirement do in Leeds and wanting to sink a fair bit of the companies beer I went by bus. The first two didn't turn up, the next one was late. £1.80 for 5 miles is probably OK, but the door to door average speed: 4.5 mph

My current trips to London I don't pay for and could actually splash out the exes and go by almost any means. But:
Leeds-Guildford by car: 3.5 - 9.5 hours, average 4 (done it dozens of times, the 9.5 was in a blizzard)
Leeds-Guildford by taxi-plane-taxi: 3.5 - 12.5 hours average 4 (done it 6 times, including the one they diverted to Newcastle after it took off 7 hours late!)
Leeds-Guildford by taxi-train-underground-train-taxi: 4-6 hours, average 5. (done it twice, the return one broke down!)
The car involves no waiting to start, no getting felt up by some bloke with an electro magnetic phalas and no sitting next to a meths drinker with a personal hygene problem. You also never turn up at the end of the M-25 a few minutes late and find they cancelled the M-1 north!
IMHO I think the technology exists to make it work better, but the fundemental flaws of railways would seem to matter less for things that don't mind a bit of waiting. Get the Freight on the rails!
I'd still rather take a train than fly mind.
Andy