As someone who loves Magic and the Pokemon TCG, I am hesitant about this angle from a personal investment perspective (as in, I don't want these things to go away, because I like them) -- but this problem is bigger and more important than my personal taste.
It would be a harsh blow to physical booster packs if this treatment extended to them, no doubt. However, regulations aren't made that way; if video game gambling was cracked down on by the ESRB or similar parties, paper card companies would have time to react before they were cornered by legislation or other regulations. It would be tough for them, but I believe they could survive a shift to alternate distribution models. Pre-built decks are already a major focus for casual players, for one; they could also look to the model used by "living card games" as a way to distribute whole new expansions. Limited formats, which rely heavily on booster packs, would be the most difficult to maintain; I honestly can't think of a better model right now than simply moving boosters out of Wal-Mart and keeping them in local game stores, allowing limited to continue to exist for those most interested in it while unfortunately taking it away from younger players. That would suck, a lot, but it might be necessary... You can't give legal exceptions just because Magic is an awesome, way-less-predatory game, unfortunately.
I'm sure Wizards and the Pokemon Company are thinking about things like this already. I have faith that they could survive, even if it would pain my heart to see them take a hit.