I'd prefer more focus on single-player and that might be a better option for them in the long run (while still making cash from online). I'd be more than willing to pay for an expansion if the main game itself is as good as I'm sure it's going to be so why don't they listen?
Online versus what GTA V is doing currently I can only guess about but I'd reckon they'd need something extra sweet to to make online pounce and pull people online. Also since I won't have online available (I refuse to pay for a subscription service just to get to play online modes even if they push extra free content with it that I'll most likely never use) it'll be a null feature for me anyway until it (if ever) releases on PC.