Site plans and the necessary subsequent permits always take a year to a year and a half for approval for
big projects. The developers in this case announced a realistic time frame. Anyone keeping up with all the big projects over the last several years may have noticed that original project start dates almost always get pushed back, and the site plans are typically not yet approved when the start dates first start slipping.
EDIT: We're just an impatient bunch here on SSP, so it seems like a long time in this case.