Because as someone else said online, it actually makes quite a bit of sense:
Think about it... Why isn't Mario in NSLU? Because he was captured by King Boo when he went off to Evershade Valley! After all, E Gadd said he called on someone else before Luigi, and most people think it's likely said individual was Mario himself! Presumably he left his hat on the Peach's Castle table just before this point too.
But because Luigi was on this quest to save Peach at the time (perhaps during the time period/cut between the lab getting wrecked and Luigi being shown at home), by the time he returned, Mario had just been captured (unbeknown to E Gadd) and the plot was in full swing.
So what do you think? Is it possible New Super Luigi U is a sort of prequel to Luigi's Mansion Dark Moon?
Think about it... Why isn't Mario in NSLU? Because he was captured by King Boo when he went off to Evershade Valley! After all, E Gadd said he called on someone else before Luigi, and most people think it's likely said individual was Mario himself! Presumably he left his hat on the Peach's Castle table just before this point too.
But because Luigi was on this quest to save Peach at the time (perhaps during the time period/cut between the lab getting wrecked and Luigi being shown at home), by the time he returned, Mario had just been captured (unbeknown to E Gadd) and the plot was in full swing.
So what do you think? Is it possible New Super Luigi U is a sort of prequel to Luigi's Mansion Dark Moon?