They also saw the Wii as an underpowered junk machine...didn't stop them from copying it...and it didn't stop the Wii from owning both Microsoft and Sony. And honestly, if Sony/Microsoft hates on a system, you know that they're quaking in their boots...and showing their new consoles at E3 2012 would only prove that point.
The difference here though, is that we're within the Wii U's launch year and the thing still hasn't generated much interest. The Wii had a massive hype train from announcement to release and that was a big reason for the success. This doesn't at all mean that the Wii U fail because it's not living up to these expectations, but at the moment we really can't determine how well it will do on the market. But I'm counting on Nintendo to pull off something amazing at E3 2012, their conferences always beat Sony and Microsoft's hands down.