Jagex would be a lot worse off, a lot of their money comes from botters hence why they hand out temporary bans now instead of permanent ones. Personally, I spend a lot of my time playing legit, I enjoy the game for what it is, even tedious tasks like soul wars I am now starting to play legit.
RuneScape would become a lot less popular, one reason being that botters make up a large majority of the population of RuneScape. Another being that if there were no botters, the prices of many resources and gathered items would rocket, for example red chincompas.