If you don't ever get a leash you're doing something wrong. There are definitely games where I don't get a leash and say in chat "hey guys, play a little safe, it's gonna take me longer to gank bc I'm low health after the first clear w/ no leash and had to back sooner so I gotta get some more camps and buy a second time since I didn't have money for health pots." Most people don't complain about lack of early ganks then, and if I'm not ganking later..... why am I not ganking?
As for leash a lot of times you get one, but having switched over to maining lanes (since the champ I like most doesn't JG :( sad day) I am surprised in the low elo my baddie self am in, how often JG tries to start in a spot that is a bad idea. I like playing heimer and you have two options when you star q as heimer. The first is to drop 3 at a camp and use the stored one plus those to kill the camp with little damage to you and go to lane at level 2.... which doesn't work for a leash. The second is to go to lane and set up turrets in lane to be ready when your opponent gets there. Either way, there is a decent chance that my leash is a couple autos before I go to lane to defend my turrets from the opponent..... that isn't a good leash and you probably aren't much better off than if you didn't get one. Similarly some melee champs have a hard time getting to lane on time vs their opponent if they give a good leash top lane and their opponent doesn't have to leash. You can lose the lane if you try to give a good leash and don't have mobility or the range to give one over a wall or something. Think about what the lanes are and if they are going to lose lane early to a bully they are facing if they miss that early exp. Then think about starting on the other side of the jg. I promise you, if it comes down to giving a good leash to a jg I don't know will perform well, or trying to win my lane and do well myself, I'll skip the leash every time if I think it will set me back too far in lane to trade in early lane fights.