Toys to life has not taken off in Japan.
Though that's not necessarily true.
Skylanders and the amiibo haven't taken off, but there are already things like Yokai Watch with its medals, and probably other stuff that I can't think of.
How are Yokai Watch medals "toys to life" though? They're just merchandising for a popular franchise. Disposable collectible toys/cards/figurines have always been popular in Japan. They're cheap enough for kids to buy regularly with pocket money, there is a random element with rarity that makes it addictive, etc.
I think that might be the crux of it though. There's no gambling element with buying toys-to-life, they cost more, and when you sell each toy specifically, it becomes very clear which are the most popular ones and which are less desirable. It's hard to stock Amiibos and Skylanders toys the same way stores stock the stuff kids usually buy in Japan. With randomization, any retailer just has to order entire cartons of one product, rather than placing orders for different individual toys in a series. This also allows them to be sold everywhere - convenience stores, news stands, supermarkets, candy stores, bookstores, etc. Not just departmental stores which have toy sections.