It’s just different. They’d all still be good drivers but it would take time to adjust. Look at drivers like Rubens who have been around for donkeys and seen the sport change. They’re still good but they learn different ways of driving.
Hamilton didn’t sound quite so confident when he was talking about driving the Mclaren and that’s not because he isn’t a great driver but because it would be so different. I guess it’s like when rules change with TC and refuelling, some just suit drivers more than others but they’d all cope.
I think driving today is still as hard just different. There was an interview with Heikki who was driving old Lotus cars (in the F1 racing mag I think) and he said he preferred driving today’s cars and that they were still hard to get the best out of them.