People seem to be getting a little crazy with this. The launch looks to be a success, though how it performs long term will be the true indicator of how much of a success it will ultimately be judged.
Right now, I think it's safe to say that many of those buying Amiibos are adult, die-hard Nintendo fans. That's great and everything but the viral kid's market is what they want. That will determine if the line becomes a "hit" or if it's just a side-business that doesn't generate any additional attention beyond existing Wii U owners before it falls off a cliff.
Let's consider the competition for a moment. As of Summer 2014, Skylanders has sold 175 million toys to consumers and brought in $2 billion dollars. Disney's Infinity topped $500 million in less than a year and is expected to grow tremendously with the addition of Marvel and Star Wars.
Now, I don't think Nintendo expects those numbers but the point still stands that they will have to convince kids to rank Amiibo toys on their wishlists higher than Skylanders and Infinity toys. That's the real battleground.
Also, I'm a bit confused about where people are getting their figures from. I find it very hard to believe that Nintendo is seeing anything near a 100% profit margin on the first run.