When the free-to-play model first started hitting the market, it caused an outcry of angry resistance from old-school MMOG "purists" that thought it signalled the death of the genre. Now, it is the monthly-fee model that is considered an oddity, with revenue models centering around real-money shops that sell various commodities that are not essential to play and advance in games. With various AA and AAA games going F2P with cash shops and services, we can see that this is the new standard model.
The question is, why is this the new standard model? Is it just because it is cheaper? Why will people play FTP models even if they intend on buying things from the cash shop - even if they spend more at cash shops than they would if they paid a subscription game where they have access to all in-game items and commodities?
It seems to me the reason is that in a FTP model, they only pay for what they actually want and can use, and they do not pay for content they don't want, or will never see anyway. IOW, in F2PCS (free to play cash shop) games, you don't pay for any content you never see or use.
In traditional monthly-fee MMOGs, you pay X amount of money every month regardless of how much time you actually spend in the game. For casual players and solers, that money pays for a huge amount of content they will never see, and pays for a lot of time they will never spend in-game. It's a no-brainer for such players to migrate to F2PCS games where they're not spending money for unused, unexperienced content, and when they do spend money, they get exactly what they pay for.
What's going to happen when (not if, but when) more MMOGs start offering offline advancement? For people that cannot devote large amounts of online time to advancing their character, but still want to be able to play and be part of an MMOG community with what time they do have available, it's again going to be a no-brainer to move to offline advancement models. It's inevitable that more games are going to offer it to time-starved MMOG enthusiasts, and it's inevitable that many players are going to migrate to a new system where the advancement of their character is not going to be limited to how much time they have to sit in front of their computers bashing keys repetitively.
Just as players want to get the best MMOG value for their dollar, and so move to FTPCS games, they also want to get the best MMOG value for their time. They don't want to log in and be forced to do things they don't really want to do just to advance their character, just as they don't want to be forced to spend money subsidizing content they will never experience. They also don't want to play MMOGs where their character advances only to level 15 in the course of a year while their friends and guildmates have already hit level 80.
The offline advancement model is as inevitable as the FTP model, especially with the original MMOG base advancing in years and finding themselves with less and less time to devote to MMOGs. With less time to spend online and less money in such an economy, the F2P Offline-Advancement model is coming. It's just a matter of what game properties realize it first.
In 3-4 years, we'll be talking about online advancement only models the same way we now talk about monthly-fee models. You can rant and rave all you want, just as you did when the FTPCS models appeared, but it won't change the tide that is surely coming.