Well, their lives would have been a lot better, and there would have been no need for deaths if they had followed the Law. Towards the end, when Mowgli brings back Shere Khan's hide, we can see that they are lawless wolves. Many were limp from falling into traps, sick from eating bad food and littered with wounds. Some wolves were missing. This would all have not happened if they had not fought against Akela (the pack leader) and disobeyed the law.
If they had not disobeyed the Law of the Jungle, perhaps the story would be different in that Mowgli would not have been driven from the pack. If he was not angered after hearing how the wolves hated him (a result of following Shere Khan), Mowgli would not have left the jungle and the pack would not have fallen apart.
The author probably wanted to show us what bad influences can do. It was also shown that being divided will bring no good. As a result of following a bad influence (Shere Khan), the wolves ended up separating from the pack. This bad teamwork caused them many wounds and woes.
Hope this helps! Have a nice day :)
