NFC figurine games are a new type of game, involving a line of figurines with RFID tags embedded within and typically a proprietary hardware NFC peripheral. Scanning these figures into the game typically allows the player to play as the character depicted on the figure, saving the character's progress within the RFID tag in the toy, among other ancillary gameplay benefits. The massive scope of many of these games' figurine line-ups poses similar problems to that of controller-heavy music games (Activision being the codifier, if not progenitor, of both types of games), which peaked and then crashed in 2010.
Figurine games are big, and not just in terms of sales. At almost every store I have seen that sells games, NFC figurine games command as much shelf space as an entire games console's library. At the most egregious end of the scale, my local Toys 'R' Us dedicates two full aisles to NFC figurine games. This is compared to the one aisle left for all other game software to share. Even the games themselves typically must come in a "starter pack" consisting of the game, some figurines, and the proprietary "portal" which allows the toys to be scanned into the game. Ridiculous uses of retail space are justifiable when the product sells well, but when a lapse in demand occurs, the inability to allocate smaller amounts of shelf space to sell the games will accellerate the downfall of the genre.
The use of proprietary scanning hardware will also serve to inhibit the growth of the genre. During the guitar game's height, every new game brought on a new set of controllers which weren't necessarily cross-compatible with other games. The biggest problem with the games was that players would accumulate mountains of proprietary, incompatible controllers which were an outright nuisance. Likewise, every new NFC figurine game means a new proprietary, incompatible portal and a whole bunch of new figurines to collect and clutter up one's living room. Portals and figurines are at least backwards-compatible within the same series, except when they aren't.
Currently the two above factors are held back by the fact that the market is currently dominated by few players. Players of both Skylanders and Disney Infinity aren't causing too much home clutter in the same way that players of both Guitar Hero and Rock Band did. But every new entry into this space compounds the problem of retail and home clutter with a new line of proprietary figures read by an incompatible portal peripheral. With more people wanting a share of this market I can't see how this is a sustainable business practice.
The current pattern of the market seems to be that every competitor to Skylanders is an already established license. You have Disney Infinity and Nintendo's amiibo figures, both of which are pulling from vast universes worth of material to create their figure lineup. Given the need for a large cast of child-recognizable characters there are a few candidates for the next big competitor to show up. DC Comics, Nickelodeon, possibly Cartoon Network, and definitely Hasbro, and DreamWorks spring to mind, especially if the latter two merge as I've heard rumors about.
So what's the endgame scenario I'm imagining? A gold rush that busts. Everybody with a large set of child-friendly licenses to pull from decides to start pushing their own figurine game based on the same concept. With fad markets, the time at which the fad collapses is typically when everyone tries to get in on it, which winds up pointing out all of the original problems with the concept. The increasing number of companies rushing out these games increases consumer skepticism in the overall product and will inevitably create a backlash based on the legitimate complaints I mentioned before. But the fact that the product is very dependent on a large retail presence will be the final nail in the coffin, as it means that we won't see a multi-year slump but a single-year crash.
Nintendo's amiibo figurine lineup seems lazer-focused on avoiding the problems with NFC figurine games. The figures are scanned with the controller your Wii U came with, and they work with a wide variety of Nintendo games at varying levels of integration. Smash seems to be the biggest user of them, as they become computer opponents with a level of learning ability (they adapt to the tactics of their past opponents). Other games typically provide either random cosmetic bonuses or function as improved computer opponents. More importantly, if you don't care about amiibo, you can ignore them entirely and still have a complete game to play.