The German won four straight titles with Red Bull, between 2010 and 2013, but has failed in his efforts since moving to Ferrari for the 2015 season.
He has been Lewis Hamilton’s closest challenger in the title race for the last two seasons, but the Brit, and Mercedes have ultimately had enough to get them over the line.
“I think we need a stronger package,” Vettel admitted.
“We certainly had our moments this year when we had strong races but we also had races which weren’t very strong, we weren’t quick enough, so I think overall it’s the speed that decides and I think more often than not I think we’re lacking a little bit of speed.
“I think we’re working very hard and the motivation is there to do that final step that is still outstanding.”
The German also added that too much focus is directed at drivers, and that there are many people behind the scenes.
“What you look at in terms of when you look in qualifying or the race, then obviously we are the ones driving the car and we are alone driving the car,” he added.
“When we cross the line you look at us first, but there’s a lot of people behind to make sure that you do cross the line and if they do their job really really well and work together then you have a high chance of finishing higher up.”
Despite the issues, the four-time World Champion believes the Scuderia have what it takes to get back to the top and to win titles again.
“We know where we want to go: A lot of work ahead of us, a lot of lessons to be learned again this year,” the German continued.
“We have 21 races and in summary, we haven’t been strong enough this year to take the challenge until the last race, the last lap, so I think we need to look at ourselves.
“I think we have the people, we have the resources so it’s more getting the maximum out of our package, improving the work inside our team and making sure that we come up with a stronger package, a stronger team for the future.”