The Netherlands international believes that the Gunners, who sold his compatriot Robin van Persie to Manchester United last summer, must hold on to their key players to retain their ambition of winning trophies every season.
"I think you can see it," he told The Sun. "It's not my opinion, it's also a fact. The last eight years — no trophies. That says it all. If you look around at the moment there are some teams in England that are maybe stronger than Arsenal. I cannot speak for Robin. He made his decision.
"Again, I live in Germany, I don't live in England, so it's very difficult for me to really judge this situation at the club.
"But if you see there are always players leaving and when they leave, at that moment, they are the most important players or the best players and, if you keep losing these players, then every time you have to try to build up again.
"Mr [Arsene] Wenger has shown that he can do it. He's a great manager, he's shown that by improving young players, but the trophies are also important."
Robben will face Arsenal on Tuesday when Bayern Munich travel to the Emirates Stadium for the first leg of their Champions League last-16 clash.