Sure "The Knowledge" is an impressive feat of learning, but more often than not the drivers don't make use of it because the best route is not the most profitable one for the driver.
I have lost count of the number of times I have been subjected to the "tourist tax" where the driver heads straight for the major artery roads with their traffic jams (e.g. Kings Road, Strand, Embankment etc.) so you get to sit there watching the meter clock up whilst you move nowhere. Or the number of times the quickest and least-traffic route is South of the river but the driver sticks religiously to the Northen route.
Or the number of times the driver fumbles slowly getting the change, in the expectation that you say "oh forget it, keep the change" ... even if that change is £4 or more !
Or when I've been driving around London only for the Black Cab in front of me to stop on a double-red line to drop off a passenger. Or make a U-Turn in the middle of a busy street.
Don't get me wrong. I'm not fond of Uber either. Their standard of driving is pretty poor, and I hate the way they sit at the Heathrow DROP-OFF area waiting for their next job.
What I am saying is that the London cabbies are in dire need of some stiff competition. Yes I would rather that competition come from someone of better quality than Uber.