Mark Lee writes in the Washington Blade (a gay newspaper):

...[The District of Columbia] Council testimony and media reports during consideration of the modern marriage bill touted extraordinary local economic benefits to come once gay and lesbian couples were permitted to marry in Washington.

Unfortunately, although no commercial benefit was — or should be — required to justify the expansion of the civil right to marry, those projections have proven overstated and the level of anticipated revenue for local businesses has not materialized.

The shortfall is due to both unrealistic economic forecasting by some marriage equality advocates and a notably lower number of same-sex marriages performed in the District than projected.