Online counting-not impossible, but not the key to the vault
Sunrunner-online counting is possible and many have tried it. Some sites do offer token penetration. Most sites which offer live video feeds do deal some fraction of the deck out.
The problem is that the game is cruddy by B&M standards, even modern B&M standards. I think this tends to put the vast majority of counters off, especially since counters tend to be naturally suspicous of online play.
This mindset tends to be over-cautious, IMHO. Counters tend to think of these games in the same way they'd think about B&M games. This is a mistake because online games have some noticeable advantages over their B&M counterparts.
Firstly, the games have zero expenses. You do not need to stump up for airfare or hoof it round Vegas. Almost everyone underestimates the impact of those things on their bankroll. Every time I sit down with a struggling counter and work out exactly what their expenses are, they are shocked.
Second, the speed of the non-live games can be very fast by B&M standards. You may be looking at 600 hands per hour, which is faster than all but the fastest dealer can deal heads-up. And, non-live games are usually (though not always) heads-up.
Third, while the penetration online is universally dreadful, this can be compensated for by the ability to shuffle-up, in some cases more or less instanteously. Something like Global Players 2-deck with 40% pen sounds horrible, but there is a big difference between a 2-decker with 40% pen regular game, and a 2-decker where your bets are made constantly at the deepest penetration level. The mathematical difference is huge.
All this said, I have had only limited success counting online, and don't know of any one who has made big money doing it. This is partly due to the fact that straight bonus hustling, even know, is a better deal. So, online counting remains an option for "special situations" such as a well-regulated operation temporarily offering a comparatively deeply-penetrated game, or a stop-gap to keep your EV up till a better promotional deal comes along. Or, sometimes, a way to make an unplayable bonus playable.
There is a further big problem-it is difficult to believe you aren't being cheated. If you are one SD at a B&M joint you can usually be fairly certain that it is just bad flux. However, online, even someone like me who has unusual faith in the integrity of online games, begins to doubt things. The trouble is, if I think there is say, only a 5% chance I'm being cheated, then that would be enough to make the whole thing negative expectation.
Finally, there is the possibility of automating your play. I have no comment on that, except to say that it is harder to build a successful counting bot than most think, and the returns on investment are usually less than stellar.
All this said, I would be surprised if sooner or later a professional, well-financed and well-organized counting team did not emerge, that could make this work. Personally however, I think there are generally much easier ways to make money gambling.