The former Barcelona defender took the helm at the Rotterdam club in 2011 and guided them to runners-up spot in his first season, before finishing third this term.
"The season was good because Feyenoord had a lot of financial problems," Koeman told reporters in Dubai.
"Maybe next season we will be champions - it will be a hard fight. PSV Eindhoven and Ajax have more financial possibilities than we have, but we have more talent.
"We have a lot of young players and next season they will be one season older. If we keep the team together we have possibilities."
The emphasis on youth is due to Feyenoord's debts, which stood at 40 million euros ($52.34 million) in 2010 and forced the club to make big cutbacks.
This strategy has borne fruit, with defenders Stefan de Vrij, Kelvin Leerdam and Bruno Martins Indi and midfielders Jordy Clasie and Tonny Vilhena in the Dutch squad for this month's UEFA European Under-21 Championship.
Yet for all the youthful promise, Feyenoord have won just two trophies this century - the 2002 UEFA Cup and 2008 Dutch Cup.
"It's difficult - if you look at the budget of the teams in Holland, Feyenoord is fifth," said Koeman, who has the rare distinction of having played for and managed all of the 'big three' clubs in the Netherlands.
Feyenoord fans remain loyal - home attendances top 45,000 despite the club last being crowned champions in 1999.
Ajax and PSV have won 12 of the 14 Dutch titles since then, but have made little recent impact in the Champions League and Koeman warned Dutch teams would continue to struggle due to the greater financial muscle of Europe's elite clubs.
"The fans know one day we can win against Manchester City, but if we play them 10 times we will lose nine and for that reason it's impossible to win the Champions League - you have to win against Madrid, Barcelona, Manchester United," said Koeman.
That was not always the case - Dutch clubs have been European champions on six occasions, most recently Ajax in 1995.
But for now, Koeman expects the Netherlands' top young players to see their domestic league as a stepping stone to bigger things, just as he did, admitting he would also like to manage abroad again having enjoyed a brief stint in charge of Valencia.
"That was a great experience and maybe there will come another moment where I again go outside Holland," added Koeman. ($1 = 0.7642 euros)
- Sports & Recreation
- PSV Eindhoven