Brundle seemed to miss that Hamilton was first about 2 seconds behind Kvyat then about 2 seconds behind Kimi. Had there been no second safety car he'd have been doing 15 laps on the supersofts at the end and been around where Kimi was, 10 seconds or so back.
You can't gage the performance difference using Rosberg, he is literally no where near Hamilton's pace and the tire strategy was ruined by the second safety car as well. Think Verstappen/Sainz at Lotus/FI at the end, that is what Hamilton would have tried against the front three.
Hamilton was basically half a second faster than Rosberg throughout the past 3 races, so taking off 25-30 seconds from Rosberg and Merc don't look anywhere near as uncompetitive.
EDIT:- I don't think Hamilton would have been that close, or Kimi as close without the safety car. Hamilton thought he was on for a win when Vettel was going slow, first stint he burned out his tires then ended up being caught, second stint he did the opposite, saved then used them up before pitting. So Brundle saying he has no idea why then using Rosberg as a pace measure is ridiculous. Sky love doing that, taking biggest and most uncomparable numbers. Banging on about P1 as a 1.5second advantage in Monza when Ferrari were 3/10ths behind in qualifying, why would you keep referring to P1 gap?