[vashishthajogi]

I agree that not all startups are like that.

Most startups that are in their early stage don't have many developers and also don't have the funding to hire an army of developers. So they only have one expert per field.

The team that I interviewed with at Apple has 4 experienced iOS developers and this team specifically uses libraries very extensively. Mostly they have libraries that they have developer in house, but when there is something better out there they try to adapt quickly.