Actually, per the quote provided earlier in the thread, he did. There's absolutely no room for confusion - disposable income strictly means income after tax, not income after tax and expenses. Reggie isn't the most knowledgeable in relation to video games, but as a marketing figure you can bet that he won't misuse a term like disposable income.
He also stated that the individual was the head of a family of four. The disposable income figure quoted obviously related to the whole family, otherwise there was no point in quoting it, as every family's purchasing decisions are based on the disposable household income, rather than on the disposable income of a single member thereof. Unless the head of household is akin to the father in Chibi-Robo.
While $50,000 - $60,000 is a very manageable disposable income for a family of four dependent on where you live, it is not necessarily going to leave you in a position to buy the latest consumer electronics. Obviously, in New York or San Francisco, for example, its not going to stretch anywhere near as far as it would in other far less expensive areas of the country.
Fair enough, this wasn't Nintendo's $599 or get a second job moment, but it did seem to indicate that at the outset the Wii U will be priced at a level more palatable to enthusiasts, the "hardcore" and families or individuals with higher discretionary income levels.