As someone fluent in four languages*, I agree. I would even argue that the opposite of an advantage is true. Consider this: it adds unnecessary cognitive load. When trying to think of a word, it comes to you in four different languages, which isn't helpful!
I speak four languages out of necessity, not by choice. When you can focus on fewer languages, your proficiency in them improves. Although I can speak four languages, I always feel as if I'm lacking a certain level of expertise in each one. I wish I only needed to speak one language, saving my mental capacity for other things. Constantly juggling languages doesn't help.
The main benefit of knowing multiple languages in everyday life is eavesdropping on people in the street speaking their language, but that's about it.
Moreover, all my friends from my country also speak four languages. Unfortunately, I don't hear of people from Moldova faring much better than others.
*My mother tongue is Romanian, but everyone in Moldova also speaks Russian (due to the Soviet past). At school, I learned French and later studied in France. I picked up English mainly through computers and the internet. Now, I'm in the Netherlands and need to learn another language, but this one is proving slow to learn. I don't feel any advantage in learning a new language either.
I would gladly trade Russian and French over knowing Dutch right now ;o) There are months when I don't speak those two so they are of little use for me anymore.