Extends to the extreme levels of SaaS-ification of fairly basic app functionality as well.

It's often simpler to build something you know than to integrate a 3rd party service, but it's highly frowned upon by a lot of devs and management.

Auth and analytics are things I'm thinking of - we have good tools to build these in-house. Also just running a database - never seen so many people afraid of installing postgres and a cronjob to back it up.