Often, it wasn't even close between Red Bull and Mercedes. It's over-simplifying a bit, but for the first half of the season Red Bull were often much quicker than Mercedes. Then their flexing wing got banned. Then in the second half of the season, Mercedes were often much quicker than Red Bull.

I think this was masked a bit by Max and Lewis being much better drivers than their team-mates. If all 4 drivers across Red Bull and Mercedes were of a similar standard, then I think we'd have seen a lot of Red Bull 1-2s in the first half of the season, and then a lot of Merc 1-2s later on. The pattern is also hidden by differing qualifying set-up, variable weather conditions, and brute luck (and in the case of Abu Dhabi, Masi ripping up the rulebook).