Every kid is different, you more than likely did everything right and they just didn't get the "bug". Don't beat yourself up, they may get the desire when they get older to spend time with you.
As it's been said don't beat yourself up too much. I took my daughter hunting with me from a very young age. I bought her a Rem 700 in .243, cut the stock down so it'd fit her, and she was dead on good with it. She told me she was ready to actually shoot a deer so I took her hunting she was around 13 years old carrying her rifle, as we sat in the box stand a doe appeared about 75 yds from us. She raised her rifle in the direction of the doe, looked through the scope, and told me she couldn't see the deer. It was foggy that morning but not that foggy, so I pointed out where the deer was again, and she said I still can't see the deer dad. I said that's ok sweetheart we can find anyone another day. She lowered the rifle and that was the last time she went hunting with me. Broke my heart then and even today 45 years later.
Now my son that's an entirely different story, he shot his first deer with me holding the rifle, 7mm Express, (yes we practiced doing that because he was hounding me to shoot a deer but he was too small to shoot the 7mm) and he touched off the 3lb trigger and recorded his first deer. He was about 6 years old then. He was probably around the age of 10 when he shot his first deer all by himself. It wasn't that we didn't try but I lost my hunting rights on the land of deer and we hunting public land close to home and that was his first opportunity. He's been hooked ever since and so far his 4 kids, 1 son, and 3 daughters go deer, black bear, and turkey hunting with him all the time, and two of the 4 have shot big game. The oldest, my granddaughter, shot a deer, turkey, and bear, my grandson shot a deer and turkey. It won't be long before he gets his sights on a black bear.