Hmmm, but if they run online casinos they will need to try to be competitive online.
If they don’t give bonuses, they don’t stand a chance, the players will go to those who will.
Online presence will be a learning curve for Vegas, they will likely be hiring or contracting entities who are currently doing well online to help.
The familiair names and legality will quite likely draw a lot more people to playing online, but these players will soon roam the net looking for better deals.
I don’t think that the current online casinos will suffer, quite the opposite. Those who hang in there should see increased revenues IMO, and Vegas will have to compete. The number of online players will surely increase a lot.