Other than the Wii, how many consoles have there actually been - successful or otherwise - that were not 'the most powerful console at the time of its release'?
You're not counting handhelds, I presume? Because apart from the Virtual Boy, no handheld before the Game Boy Advance came anywhere near the Lynx in hardware power and features. It beats the GB, GG, GBC, NGP/C, WS/C, Game.com, etc. in everything except for resolution, pretty much.
As for consoles though, you're right that it's much rarer, but it has happened on occasion -- the PC Engine FX released in late '94 in Japan, the same time as the Saturn and Playstation, but was nowhere near as powerful as either one, for example. The Neo Geo CD launched at that same time, and it also was weaker than Saturn and PSX in some regards (3d, most notably, was something that neither the NGCD or PCEFX had any ability at).
For another thing, it wasn't an entirely new system, but the 32X released in Japan AFTER the Saturn, and the 32X released in the US the same month the Saturn did in Japan. And that aside the 32X wasn't more powerful than the 3DO or Jaguar either, really, so it wasn't the most powerful system out there for sure. But that is an addon, so it's a somewhat different case.
On a different note, and what about the Atari 7800? Was it really more powerful than the NES? It did release after it. Even the original 1984 date would be after the 1983 Japanese Famicom launch.
In addition, while the 7800 and Master System had improved visuals over older consoles, neither could match the NES's audio, particularly the 7800 and its audio chip straight from the 2600 (even though the 5200 had had much improved sound)... and the Game Gear has the same problem as the SMS, and has worse sound than the GB. But sound always got overlooked in favor of graphics.
Anyway though, yes, you're right that a new console with last-gen power is rare, it's not entirely unheard of. The Neo Geo CD was exactly that for instance. (I'll ignore the 5200 vs. 7800 issue, I consider the 5200 and Colecovision to be a new generation, not part of the same 2nd gen the 2600 is in). What was new was a system like that winning.
If it were any other company I might be concerned, but every Nintendo system has been progressively smaller or really close to the same size. NES was bigger than SNES which was bigger than N64 which was about the same size as GC & Wii. Nintendo are pretty good at packing a lot of power into a small package.
The Gamecube's bigger than it looks, they just used a vertical orientation to disguise it... I'd imagine a space comparison would show it's bigger than the N64 for sure, though I'd expect that given that it has a disc drive.
I think it's worth pointing out that the most powerful console never wins.
Master System was more powerful than the NES.
N64 was more powerful than the PS1.
Gamecube AND XBox were more powerful than the PS2.
360 and PS3 are more powerful than the Wii.
Lynx, Game Gear, TurboExpress and Game.com were all more powerful than the Game Boy.
Wonderswan Pocket and NeoGeo Pocket were more powerful than the Game Boy Color.
PSP was more powerful than the DS.
Vita is more powerful than the 3DS.
So I imagine you didn't mention the SNES beating the Genesis and Turbografx because that's the one example of the more powerful system winning?
I admit, there was a more powerful system out there that gen, but the Neo-Geo wasn't exactly something most people could afford. And yes, the Genesis plus Sega CD and 32X is almost certainly more powerful than the SNES, even with Super FX 2. However, of the consumer-affordable systems that gen, not counting addons, the winner had the most powerful hardware. But yes, that is the only case.
