In addition to the above comments, Vettel is a supreme qualifier whereas Alonso, as good as he is, is not on par with the likes of Hamilton or Vettel over 1 lap, which would give Vettel the edge on certain tracks like Monaco.
There’s no evidence behind that whatsoever, especially considering that Vettel and Alonso have never driven for the same team.
Fact of the matter is, Alonso has a better qualifying record against Massa than Vettel does against Webber; and most people rate Webber and Massa very similarly, good but not great drivers.
It’s a well known fact that Ferrari struggle to get heat in the tyres, while Red Bull are usually among the best at doing this. Ferrari however, are great at making the tyres last, better than Red Bull. That’s why Ferrari’s race pace is often better than Red Bull, comparative to their qualifying pace.
If Vettel drove the Ferrari over the past 3-4 years, you likely wouldn’t rate him as a great qualifier either. Likewise, if Alonso drove a Red Bull in the past 3-4 years, his one-lap pace would be rated much higher.
However, it works the other way too, if Vettel drove a Red Bull, people would rate his race craft much stronger, because Ferrari is better at making the tyres last, and has more top speed, which makes it easier to overtake. Likewise, if Alonso drove an RBR, his reputation as a racecraft master wouldn’t be as well-recognized.
In the 2007 qualifying battle between Hamilton and Alonso, the average difference in Q3 laptime was only a mere 0.018 s in Lewis’ favor, discluding France and Germany, where one of the two didn’t set a final laptime for some reason.
OK, my rant is over, lol.