Webber drove most of the race in the lead, your tires last a lot longer there as all the professional commentators (like ex-drivers) have said countless times over the season. It's also possible that Lotus/Renault just can't utilize supersofts as well/long as others Different positions on track (like webber comparison) matter, as does the car - when his laptimes suddenly plummeted the team should have acted then, not several laps later when the gap to Vettel had grown so big. F1 strategy isn't just about watching what other teams do, but how your own teams cars do, too. If your teams car suddenly slows down up to several seconds per lap compared to how it was going before, you pit it immediately, not when the gap is far too big to be really caught up by driving.