My Wusthof Knife is NEVER sharp enough...please help!

Hey everyone. I splurged last year when my knife set got stolen and purchased a Wusthoff 10 inch chef's knife. I have had this knife professionally sharpened numerous times, and use a steel before and after each use religiously. Could someone please explain to me why my knife if completely dull and won't cut through even an onion a mere three days after being sharpened? Do I need a better steel?

Also, please note that I used to live in Chicago and went to a great place to get it sharpened, and it still happened. Now I am living in Adelaide, South Australia with nothing but a key shop that sometimes sharpens knives, so my options are more limited. I know this knife can work, so any advice would be greatly appreciated. Thanks!