Since Opera became increasingly bad in the last 8 years or so (I didn't use it before), I assume that the people which are still using Opera actually are pretty sticky.

I can't imagine how this could possibly work for them. Maybe there are sticky users who've been on Opera for decades, but it's gotta be niche as hell. I remember Opera being great 15-20 years ago -- it was my browser of choice. As far as I know nothing differentiates it these days from other Chromium browsers.

In my circles, Opera was dead when Presto was killed. I don't know anyone who uses Opera today, except an apprentice we had for three months last year.

In theory, it should just have been a change under the hood - use a different browser engine. But it seems that part is way more interlocked with the overall UX of the whole browser. 90% of features were missing after the switch, and while many were reimplemented later, whenever I checked it out again it was just different. I stuck with Opera 12 for so long it wasn't even funny anymore, more and more pages broke every day, but eventually, slowly I got used to Firefox. Which really took a loooooong time, since I tried a lot of extensions and tweaks to make it feel right. Weird how strongly you can get attached to a browser and its UX. I think even switching from Windows to Linux wasn't that tough.

I think a lot of the remaining Opera use is Opera Mini, possibly for its page size reducing proxy setup. On a site I do moderation for a noticeable amount of our most blatant trolling comes from that.

Interesting