There are two often-quoted sets of numbers on the state of the camera market, and they measure different things. The CIPA numbers do NOT break out brands, but they measure worldwide sales of cameras by Japanese companies. They are fairly complete, because almost every dedicated camera is made by a Japanese company (cameras built into other things aren't necessarily, but CIPA doesn't count those). Samsung (Korean) and a number of small European companies, of which Leica is almost certainly the largest, are missing from the CIPA numbers, but none are major sellers, unless Samsung is gaining share in compact cameras, which could make the "compact collapse" look worse than it is?
The BCN rankings (which are often quoted for brand shares) are more restricted than that, and in two very important ways. First, they only measure cameras sold within Japan, and second, they only report number of units sold, not revenue or profit (CIPA doesn't report profit, but they do report revenue. BCN is essentially a ranking of how successfully manufacturers move the low end of their product line in Japan (the high end is included, but so many fewer D5s are sold than D3300s (for example) that the D5 essentially disappears. Every market is different, and the Japanese market has a couple of idiosyncrasies, which are partially shared with other Asian markets, but not with the West. Many Asian buyers of entry-level cameras prize compactness above all else, and they are willing to tolerate the loss of the viewfinder to get there. This isn't true of serious photographers, of course, but BCN measures units sold, so it is driven by consumer tastes, not serious photographer preferences.
The big "winner" in mirrorless from BCN's reporting is Canon. Every body they sell is low-end (once you get off the lowest rung, they want to move you to a DSLR), and none of them have viewfinders. The EOS-M line sells so poorly outside Asia that Canon USA has refused to import some models, but it sells relatively well in Japan - anecdotally, largely to young women whose previous camera was a phone. Nikon and Pentax also sell a fair number of mirrorless cameras into a similar demographic - hampered in the West by small sensors and lack of viewfinders, their lower-end models sell to casual photographers in Asia who prize compactness (and whose Western equivalents don't buy mirrorless cameras at all).
Olympus also benefits from how BCN reports - their higher-end OM-D line sells worldwide, but the PEN line of viewfinderless cameras (the new PEN-F is not really a PEN - it's an OM-D in a retro jacket) sells primarily in Asia. Walk into a US camera shop, and the least expensive Olympus mirrorless camera is probably an E-M10II, unless they have an older OM-D on clearance. That camera is more expensive than a number of DSLRs they are selling, and appeals to a discerning buyer. In Asia, they'd have a number of PEN models starting at $300 or so with a lens that play in the lower end of the market.
The big "loser" may well be Fuji. Their bodies are concentrated around a higher-end set of specifications with beautiful viewfinders and excellent controls, and they love to make gorgeous, expensive lenses. Photographers love them for it, but that isn't what drives BCN rankings. They have a profitable mirrorless business with somewhere between 7% and 10% worldwide market share, and more of the revenue than that, because their average mirrorless sale is higher than, say, Canon's.
Sony, interestingly, has been moving AWAY from what would win them BCN share - they've been focusing on higher-end cameras that will never sell many units. An A5100 with the execrable little 16-50 powerzoom and an A7rII with the new 24-70 f2.8 G-Master both count as "one camera" to BCN, and, by focusing on selling the latter, Sony will lose BCN share (although neither revenue nor profit).
If I had to guess at real importance in the mirrorless market (and there are no good numbers on this), Canon and to a lesser extent Olympus are over-reported by BCN, while Fuji and Sony suffer. Worldwide rankings would look something like.
1.)Sony
2.)Olympus
3.) All of Panasonic, Canon and Fuji are probably pretty close here, although Panasonic is focusing on video, Canon on the low end, and Fuji on the high end
The lower tier includes Nikon and Pentax, who didn't crack the top 3 in Japan, despite BCN-friendly lineups.
In terms of who's actually got a sustainable business, it's Sony and Fuji almost for sure, and probably Olympus (who seem to have finally turned a profit on mirrorless). Panasonic may, although I'm quite suspicious they lose money on the low end of their line and make it up on the video-focused top. They ALSO have a very well-known pro video division, so it wouldn't shock me if they eventually got out of the low end and gave the successful GH, GX and possibly G series to their own video folks.
I'm not sure about Canon - it may not cost that much to throw some Rebel bits in a compact case, turn the live view on permanently, and sell it cheap...
