Attrition is never really about salary. Salary is what people say in exit interviews because it is easier to say than the truth.
The truth is usually one of four things: a manager they could not work with, work that had no meaning, no visibility into where their career was going, or a culture that said one thing and did another. Companies that reduce attrition do the harder work of understanding which one is driving people out — and then changing it.
A Friday team lunch does not fix a manager problem. Before adding perks, run a structured diagnostic: exit-interview data, pulse surveys and manager interviews to find the actual causes rather than the proximate ones.
Retention is buildable. It just is not buyable.