In a word, YES. Genetics is huge but so is training. You could be genetically superior but without proper training your just going to be average. One odd thing though, Eddie Mercx hadn't rode a bike in 20 years, gained some mid girth weight and got on it about two or three years ago and went for a ride averaging 21mph for an hour leaving far younger journalists gasping trying to keep up and most gave up! Obviously his genetics are superior to most. So if your not gifted genetically but train smart and really hard you could do reasonably well and even win local events since most, if not all the riders in those type of events would not be genetically gifted as well.

Personally to be successful at pro level racing in any physical sport, genetics is more important then training as your base to work from. By the way politics is also very important to get into pro level anything.