Funk-
They don't go after AOL, Microsoft etc., because those guys will find you. They have the tech, resources and law enforcement connections.
BillDozer-
Could you please explain your statement: "please be advised that Pinnacle Sports website is no vulnerable to hackers"
Have you bullet-proofed your connections or just paid off this particular group? Once other hackers figured out that you've paid, they'll probably come after you too. You would have been better off spending $30K on security software/hardware. I wish you guys luck, but no site is invulnerable to hackers (especially, if they only paid the ransom and didn't boost security).
Hollywood-
Hang tough! It's a battle, but every attack has a counter attack. If they are not going to get paid, they can only devote so many resources to attacking you. Attacks on you take away resources from attacks on other sites. How many sites can they attack at once?
DOS attacks generally are short-lived because the ISPs eventually get involved or the victims buy a DOS solution from some security company.