Woah woah woah, too complicated? Perhaps it is too complicated for their Big Bang Theory Sheldon like minds. I would automatically assume that people would say that Pokemon TCG is a game that takes no skill, because it is a children's card game, but too complicated? C'mon man.
The one problem of why the game isn't growing is because it is trying to cater to a niche market. The game doesn't grow if you cater to the same people all the time. That is why there are geographical patches where the game isn't played because its competitors Magic and Yugioh tries to spread the game, rather than market to a larger target audience, which are older kids, rather than have this sense that this is a kids game. Kids don't even play the game that much, but younger teens do. Even the younger kids have this misunderstanding that Pokemon TCG is a kids game, and they would feel like they have "devolved" if they played this game, it is all due to marketing.
Of the 3 TCGs I follow, Pokemon, Magic, and Yugioh, I probably learned Pokemon TCG the quickest. It took me a few games to get a grip on Magic, and I still haven't learned Yugioh thoroughly yet. Those 4 digit life points are hard to keep track in your mind, and those small text boxes that require a magnifying glass to read. It isn't to say that I don't have any yugioh cards, because I have a fair share of yugioh cards. Because I started buying Magic packs earlier, I have more MTG cards over Pokemon and Yugioh.
I'm just sad that Pokemon TCG isn't played in more places.