This is what disruption is all about: Well-managed companies failing. Epic seems to be a pretty well-run company; I don't know what its recent financials look like but Gears is popular and Unreal Tournament is still doing okay, not to mention sales of the Unreal engine.
Rein tells us "[Third party core games] are huge financial flops...It's just not where the market is." He's not wrong, there are a lot of core Wii games with mediocre or bad sales, and Epic's focus to date (graphics) makes Wii a bad platform for them. In other words, he's telling us that Wii has crummy customers that aren't very profitable and Epic is going to stick to the tried-and-true high-end customers that pay Epic tons of money.
This seems like a smart move. He's managing correctly. Just like most upmarket competitors, he has (apparently) correctly argued that the new market isn't worth fighting for.
The problem is that if Nintendo is right, if disruption is real, then Epic is going to have to change it's tune or it will be erased from the gaming scene. Wii is already marginalizing Epic: a decade ago Epic could have released a new engine for all three consoles. Now its engine is only relevant for 50% of the home consoles on the market. If Wii graphics are good enough for the majority of gamers, or even if 360 graphics are good enough for the majority of gamers, where does that leave Epic on the next round of systems? Why should developers buy Unreal Engine 4 if the next MS and Sony consoles are just "1.5" systems like the Wii? Historically disruptors drive their competition out of the business as the disruptor's new values take over.
We can debate whether disruption is real or if Nintendo is successfully carrying it out, but given the turnaround Nintendo has achieved this generation, I'm inclined to guess that the Big N's strategy is a lot more in tune with what the public wants than Epic.