There's often a disconnect between the technical staff who write customer-facing documentation vs the backend engineering teams.
Often the technical writers will be working closely with real customers. The customers will come to them 90% of the time with hacky custom jQuery stores + the support staff won't be highly skilled Front-end engineers (usually a junior-dev grasp of JS/web dev).
Judging the visible output as a metric for how many developers a company needs is very naive.
Think about the teams that don't directly interact with the outside like infrastructure, business intelligence, hiring (onboarding tools), internal tooling, all the work they do on Ruby (https://shopify.engineering/shopify-ruby-at-scale-research-i...).
Often the technical writers will be working closely with real customers. The customers will come to them 90% of the time with hacky custom jQuery stores + the support staff won't be highly skilled Front-end engineers (usually a junior-dev grasp of JS/web dev).