the.com/institution
A habit so widespread it built itself a building and hired staff.
means An established organization or custom that society treats as durable, official, and worth maintaining.
from From Latin instituere, to set up or establish — literally to make something stand in place and stay there.
Double meaningAlso slang for a long-stay psychiatric or care facility.
Living personA beloved local fixture can become an institution too.
Economists' viewRules, not buildings, are the institutions that shape economies.