Have you taught yourself your whole job?

I was reflecting on my career so far, and I realized I’ve taught myself pretty complicated software systems multiple times now. Either the person who was in the role before me quit before I started or they were too burnt out and provided the absolute bare minimum overview. I know training has been thrown out the window for most jobs (which is ridiculous), but I’m curious if anyone else out there has a similar track record and wants to share stories.