Seeing it was the most successful non-handheld for Nintendo ever, it obviously was the right decision.
if it was the right direction then people would have also been drawn to the Wii U, which they werent. the Wii hit the market at just the right time to capitalize on the casual market, because motion controls is just the type of zany bullshit that casuals are drawn to. but much like anything else society gets ahold of, it was gone faster than it arrived and then smartphones showed up to be the next zany bullshit product that all the casuals needed. the Wii wasnt even really a gaming console in the same respect as others, it was a casual device
Why would people that liked the Wii like the WiiU? Despite the similar name the WiiU was different in practically every aspect. The WiiU was a new attempt at the Gamecube, and as the first Gamecube it failed.
And that the casuals moved on is an assumption that never had real ground. The companies (including Nintendo) dropped producing games for casuals towards the end of the life of the Wii. That lead to the crash of the Wii-sales. The only casual IP that was released onwards - Just Dance - showed that the casuals were still there. The sales of Just Dance declined slowly, as over years this was only IP produced for this group. Would you stay in gaming for years, if only once a year a game is released you like?