yeah, but I got the impression that the EU is very much doing it as a retaliation to the US and UK doing it. Tho they could have limited it to just those countries.
The US, maybe. But wiki suggests ETIAS (the EU one) was proposed in 2016 whereas the UK ETA idea was created around 2023, so ETIAS can't be a reaction to ETA - perhaps the other way round?
I'm not sure if, without Brexit, the UK would have ended up with ETIAS anyway - it's a "mostly Schengen but not exactly" thing so it would have depended on what agreement they came to.
My impression was that the EU did it to prevent people doing visa-free layovers from claiming asylum, while the UK did it to negotiate a dual exception with the EU in the future.
ETA is a visa to the entire world in all but name. I'm not looking forward to the future where every county implements is and visa-free travel becomes a thing of the past.
I'm not sure if, without Brexit, the UK would have ended up with ETIAS anyway - it's a "mostly Schengen but not exactly" thing so it would have depended on what agreement they came to.