Initially when I saw that Twitter was potentially laying off heaps of engineers I did think that it was a bad move. I must admit though after reading DHH's comment on the situation my feelings have become mixed. This especially made my think twice:
When WhatsApp was sold to Facebook in 2014, it had almost half a billion monthly users, but a team of just 50 people running everything
Less engineers is often better to get big things done. More engineers lead to big group meetings and lots of disagreement on the technical direction. This can sometimes be a good thing but my personal feelings are that small teams are best.