Permit delays introduce huge costs. While a developer is durdling around waiting for building approval they still need to finance the damn thing. At current interest rates every month in delay should work out to something like a 0.3% increase in costs. When we're talking about developments hovering on the border of profitability, this can make or break a project.
If you think about the current incentives for the DOBs that makes sense. Their KPI is essentially number of inspections, violations, plan re-views. How quickly the permits get done is usually not on the list.
It's not uncommon in NYC to go for more then a year through a permitting process for 1 to 3 family reno. That's one of the reason there was so much illegal construction happening here in the past.