Some people get into self hosting just because they're interested in the mechanics of it, but many people I think got inducted by the fact that for example, Facebook or snapchat make it so difficult to save your own pictures or migrate to another service, or the possibility that Google is reading all of your emails, etc. Others may have been radicalized by a specific event, such as a service provider closing up business and therefore you lose your data.
For me, it was Spore com. I loved Spore, from the time I got it for my 10th birthday to maybe the age of 16 or 17 I poured hundreds or probably thousands of hours into this game. As I got older I became less invested in the gameplay and more invested in the creative aspect of it. I designed some badass creatures and spaceships that I was really proud of. I had a whole line of Spaceships that all served different roles in my head cannon, with different races of aliens following different themes.
EA/Maxis/whoever runs Spore now purged all of them from spore.com, and now they're gone. Years of my childhood essentially put into a locked box and the key thrown away. For me it was like losing a scrapbook in a fire. What right did they have?
So I ask, What radicalized you?
I had some plugs that I discovered I could flash custom firmware to. It taught me a few skills that I’m still a novice in level in, but I understand much more than when I started with.
I started out with Tasmota and eventually moved over to ESPHome. I’ve taken quite a few products out of the cloud over the years with it including some for friends.
Those devices, plus HomeKits as well as Zigbee as you mentioned are all great and all a central part in my Home Automation.