|Hamilton leads Rosberg during the 2013 Malaysian GP.|
Mercedes gave them that opportunity.
2014The 2014 season saw the introduction of complicated new power units, which included a 1.6L V-6 turbo as well as a 160HP Energy Recovery Unit, which recaptured power under braking. Mercedes had been preparing for that change for several years, and from the first practice session in the winter of 2014 it became clear that their power unit and chassis were the class of the field. In a sport where a quarter of a second is a massive gap, the Mercedes cars were routinely one to one-and-a-half seconds per lap quicker than Ferrari, McLaren, and defending four-time champions Red Bull.
It quickly became evident that this would become a two-man race to the championship. A Mercedes car would claim the pole position in each of the 19 Grands Prix that year, winning 16 of the 19 races. Daniel Ricciardo of Red Bull was the only non-Mercedes driver to claim a race victory.
However, this two-person race devolved into a heated battle, as the relationship between the teammates quickly soured. The low point of the season was the Belgian Grand Prix, in which Rosberg and Hamilton collided on the second lap. Hamilton retired, while Rosberg went on to win, giving him a 29 point lead in the championship.
Hamilton would storm back, winning six of the remaining seven races -- including the widely-mocked "double points" season finale -- to clinch the championship by 67 points. During that stretch Nico continued to place his car on pole position, but failed to convert three of his four poles to victory.
2015The start of the 2015 signaled that the season would simply be a continuation of the previous year of Mercedes dominance. The first race of the year saw Hamilton and Rosberg finish 30 seconds clear of third-place Sebastian Vettel, now at Ferrari. Mercedes would once again go on to win 16 of the 19 races, with Vettel being the only other driver to claim the top spot on the podium.
The main difference between the previous year was Hamilton's ability to dominate qualifying and shake the technical gremlins that seemed to plague him in 2014. That year had seen him retire from Australia after claiming the pole, have a front brake disc explode during the first stage of qualifying at Germany, and have his engine (and back half of his car) catch fire during the first stage of qualifying in the next round at Hungary. Not hobbled by starting at the back of the field, Hamilton wrapped up his third World Championship by winning the United States Grand Prix, the 16th race of the year.
Elo RatingsThis graph shows the Elo ratings of Rosberg (light blue) and Hamilton (dark blue) throughout the 2014 and 2015 seasons, along with the rest of the field (light gray).
The 2014 season is the story of Mercedes separating themselves from the rest of the pack, and of Nico Rosberg failing to convert even half his 11 pole positions into wins. Prior to that year, 10 drivers had claimed 10 or more pole positions in a single year, and nine of them had won the championship that year (the only previous driver to fall short was Ayrton Senna in 1989, losing out to Alain Prost in a contentious year).
The tragedy of 2014 is that Nico Rosberg had one of the 20 best seasons in Formula One history, and failed to win the championship. Hamilton's season didn't even crack the top 40 -- nor did he finish the season with a higher rating than Rosberg -- but he won his second title. After qualifying 21st in Hungary due to his car fire, Hamilton's qualifying woes had plummeted him to 10th place in the Elo ratings. By the end of the season, though, Hamilton had brought his rating back up to 1681 and captured his second title.
The 2015 season was the story of Hamilton's dominance at a historic level. He took the lead from Rosberg by claiming pole at round 2 in Malaysia and never looked back. His average season rating tied that of Schumacher's 2002 title run for fifth-best in the modern Formula One era.
Vettel improved his rating (slightly) from the previous year, but the gap between Mercedes and the rest of the field grew. It wasn't that Rosberg got that much worse than the previous year, as his score dropped only 27 points; it was that Hamilton improved by over 200 points in a single year.
Early reports from 2016 indicate that this year may be more of the same. Rosberg did have a comeback at the end of the season to win the final three races, but Hamilton admitted he had lost some of his motivation after winning the title. The Elo ratings support the hypothesis that Rosberg has a ceiling at "excellent but not legendary" while Hamilton has a potential of "all-time great."