I think toy interest is down not so much because kids have changed and wouldn't be interested but because there isn't really much that is actually worth being excited about any more. Naturally a kid would say that toys are lame because he is growing up in an era where most of them are indeed lame.

Just look at the rubbish that is on the shelves now.

On the other hand, Lego seems to be doing alright and so a girl toys apparently - Just Mattel mishandling the market as they usually do. It's just the action figure/Boy's toys which are suffering because their quality and innovation have deteriorated to a point not even kids want them.

Also the 'medium' promoting the toys isn't that great. We haven't had a good Transformers cartoon that becomes a sensation in a very long time (I think Beast Wars was the last one? Other cartoons did ok but didn't stand out above most as a whole) and Bay movies despite 'mixed perceptions' seem to be a 'watch and forget' affair and you need enduring appeal to sell toys.