Ricciardo is not so much better than Vettel, as 2014 seemed to show.
Because if he was, it would throw the whole driver status dynamic out of whack.
Comparing drivers with long-term teammates is the most reliable way we have of seeing where two drivers stand.
For example, Alonso used to be less than a tenth behind Hamilton in qualifying, in 2007.
Hamilton to Button, the gap used to be 2 to 3 tenths in qualifying, over 3 years. This would tell us it would be similar to that if Alonso was Button's teammate.
And from 2015 to 2016, that is indeed the gap Alonso had to Button.
Alonso dominated Massa speedwise from 2010 to 2013, so it was obvious the same would happen to Raikkonen. People hyped the partnership, but 2014 made it clear that Alonso dominated Raikkonen the same way he dominated Massa. Maybe even a little more, which is accurate, since Massa used to be a little quicker than Raikkonen in qualifying.
So, if we use this basis, and assume 2014 to be an accurate reflection of Ricciardo vs Vettel, then:
Ricciardo is even better than Alonso, because Alonso dominated Raikkonen in qualifying, while Vettel also has good speed over Raikkonen. So Alonso is only a little better than Vettel, speedwise.
Alonso's gap to Massa is similar to how Schumacher dominated Massa. Hence, Alonso and Schumacher are similar speedwise, with Ricciardo still a healthy chunk faster than both!
I could still have maybe digested it till this point, Ricciardo could well have been the fastest driver ever, it's not preposterous. He certainly did have excellent racecraft, speed, and consistency.
(Although one sign that was an anomaly in the domination was rain. Whenever it rained, even in 2014, Vettel easily outpaced Ricciardo in qualifying and seemed faster. Verstappen seems faster than Ricciardo in the rain too.)
But then Verstappen comes along. And he has even greater racecraft, though granted he makes mistakes which I think will iron out with age, and he seems to be even faster than Ricciardo now, in every qualifying. That would make it ludicrious, that Verstappen is ages, ages better than Schumacher and Alonso in raw speed.
And I don't believe we such jumps of talent in F1, ever. The odds of Ricciardo and Verstappen BOTH being the fastest drivers ever by some margin, and ending up in the same era and same team, are really, really improbable.
So, I believe that because of issues in his motivation, not liking the cars, not working well with the tyres which used to be his specialty, and ultimately teammate pressure, Vettel underperformed in 2014.
But of course Ricciardo was better in 2014.
If I had to say what would happen between them when both are in good form, with a gun to my head? Vettel will beat Ricciardo by a smidgen in qualifying. The race would be very close, as Vettel might manage his tyres slightly better, while Ricciardo has the better racecraft. But they'll overall be very evenly matched, not domination like 2014.
It's like Raikkonen and Massa, 2007 and 2008, actually. Raikkonen was just slightly better in 2007. Due to low motivation, then some bad luck in races, losing the points lead, and car not suiting him, he fell a long way behind Massa. If we had only used 2008 as a comparison for Raikkonen and Massa, we'd not get an accurate picture. I believe similar things happened in 2014 between Vettel and Ricciardo. They would be, IMO, very, very similar, with differing strengths.