People where hiring because their valuations were large. All the organisations now had to grow into that valuation. Expansion and contraction of head count is a normal thing in an orgs life-cycle that reflects the economy. CEO's job is to think about the stakeholders first and then employees. There are not many levers to play with to adjust the net revenue, growth and valuations. Growth have become stagnant or even lower, revenues are impacted and valuations are down. Only lever that is in control is head count others are dictated by external forces.

PS. No one employee was complaining when these companies were in a hiring spree and could see it was not sustainable. Startup had a hard time competing with the salaries offered by these orgs.