It may not all be doom and gloom. Landlords have been forcing long term leases (7 years+) on tenants to get space in the city. Once a company outgrows that space they're still on the line for that lease, so they sublease it out and not at a major discount.
One data point: we signed a sublease 3 months ago at 18-20% lower than market. This was a 10k+ sqft space in a Class A building in FiDi. Also notable: other subleases at the time were ~10% off.