He still loves games and hates practice (nothing new here) but I try to explain that only through hard work in practice will he A. Get playing time, B. Get better.
Two things - doesn't every practice involve a scrimmage? My son's practices always do, though it isn't the entire practice
Also, working hard in practice will get you more in tune with playing with your teammates, and help you understand where you need to position yourself, but to get better, you need to practice drills and work on skills outside of practice.