Affordable to you or affordable to the locals? The yen has devalued a lot in the past decade or so, giving foreigners a lot more spending power in Japan and causing the current tourism boom and backlash.
You can definitely see affects of the poor economy lately (lots of pawn shops popping up, replacing expensive cafes/restaurants), but housing is still reasonable for now.
Also, if you're trying to save money as a local, moving just 3–4 train stops away often makes a noticeable difference in rent or hotel prices.