Maybe. Earnings are irrelevant though, it's the amount of profit you make, which mattters.
Going by your figures, I'd reckon it would cost more than £40 extra a day to run a brand new £70,000 LWB Lux car, compared to a 8 year old Prius (I know these are the extreme ends of the scale, but it's perfectly possible).
Therefore, an experienced X driver who knows where the work and knows their way around London, will earn more in their 8 year old Prius (who paid cash outright for their car), than the new Lux driver, who has just entered the trade, financed to the hilt, with £1k monthly leasing payments.
Turnover is vanity, profit is sanity.