I don't see why people get caught up in the number of Championships a driver has won, it's a pretty meaningless stat when you consider the car and team influences/orders are often the primary reasons for a drivers success. Look at how Red Bull ruined Vettel's final season when they knew he was going to Ferrari, Ricciardo was obviously given the treatment that Vettel had received against Webber all of those years.
I honestly believe that as good as a car can be, every driver has the ability to master a specific set of circumstances and therefore some cars suit other drivers better. The people who are adaptable to many cars make excellent development/midfield drivers but rarely come out on top when things line up perfectly.
The way I view the Webber/Vettel/Ric RBR thing is basically that once Vettel had a car that he understood and fitted his driving style, he almost melded and became one with the car. Until that point, when Renault were struggling with generating the diffuser airflow that Newey's design needed to work, Webber was on top because he was more able to make the car work, just not 100%.
The 2014 engine changes would have meant that both drivers were having to learn the car again from scratch, which might have worked against Vettel to a greater extent than Ricciardo.
I suppose what I'm saying is this: Some drivers can jump in and drive any car at 95% of what it is capable of, and are always there or thereabouts straight out of the block. Some drivers are capable of driving the car at 100%, but take a little while to find the groove.
I think drivers like Vettel are in the second group of drivers - they need things to be exactly right and when that all aligns they are unstoppable.
There's a third category of driver, people like Fangio, Schumacher, Senna and maybe one or two other drivers who were just naturally able to extract the maximum from the car straight away.
