If you are a company, then you have to move everyone over and they have to learn the new software, and Karen from accounting and others needs a lot of help switching and what the app on her phone. "The old one was much nicer", "I don't know Markdown". Now Karen hates the new system.

If you self-host then you have to pay for a server. That server needs updates and backups so that is even more time. A server on AWS can just disappear overnight, so you need to prepare for that.

And yet people still go to Starbucks and buy expensive coffee without thinking.