Vettel secured his fourth successive drivers' championship with victory in India last weekend as the Red Bull proved far too strong for the rest of the field yet again.
The German driver has now drawn level with Prost as a quadruple champion and is the youngest to achieve such an accolade. Next in his sights are the records of Juan Manuel Fangio (five titles) while Michael Schumacher leads the all-time list with seven.
Prost, whose own four titles came over an eight-year period, feels that Vettel's consistent title-winning form has put drivers such as Lewis Hamilton, Fernando Alonso and Kimi Raikkonen, who have four titles between them, totally in the shade.
"It is difficult for those guys to get those four years back," said Prost.
"When you are a racing driver, it is difficult because you are only aiming at the championship. I remember when I was competing, I wanted to be fighting for the championship every year. I wanted to be in contention for as long as possible.
"I had a year at Ferrari in 1991 and I knew from the beginning of the season that it was not going to be the case. It is difficult not to compete for the championship and knowing that by the middle of the year that you are gone.
"That is the most difficult thing for a top driver. Lewis and Mercedes must be thinking that right now. They know day by day that it is difficult to compete."
As well as being the youngest to take a quartet of titles, Vettel is also the only man to win them all with the same team.
But Prost does not believe Vettel needs to leave Red Bull - the best team in the sport by some distance - for pastures new to appease those who would like him to replicate such achievements elsewhere.
"If he moved from Red Bull today and won with the new regulations and everything for sure it would help (secure his legacy)," said Prost.
"But we have to be realistic, if I was in his position I would not move. I moved myself for different reasons. Honestly, if Ayrton (Senna) had not come into the team maybe I could have continued with McLaren forever.
"You never move saying that you want the public to have a good perception of me so I will move, there is no way, it doesn't work like this. He is only 26 so we will see what is going to happen."
Prost raced in an era where team-mate rivalries were rife and had a fair share of his own, with his battles against Senna at McLaren still remembered today.
But the 58-year-old, who now works as an ambassador for Renault, believes in the modern era it can only benefit the front-running teams to have a defined number one driver, a warning to Daniel Ricciardo as he prepares to partner Vettel next year when fellow Australian Mark Webber leaves the sport.
He said: "When you are talking about modern Formula One a big constructor and a big team has a number one and a number two.
"They know what they want to do with number one and number two, there is a strategy behind that and that may be what the public don't want to see any more.
"At least if the Red Bulls dominate, they (the public) don't care very much about the domination of one team but they want to see the two guys fighting. But it is not Sebastian's fault, you cannot blame a driver for that. It is a shame but I would prefer to be in his position.
"It is always a little bit difficult to judge, there is so much investment and money involved. As a team owner I would be very happy to have a number one and a number two if I was very confident in the number one to win the title because that is how to do it. A team is a team.
"Vettel has to be the team's number one next season. He has to be. You don't want to destabilise a team coping with new regulations by signing another top driver. What is the advantage of creating another problem?"