Yeah, ETIAS has been discussed since Brexit in 2016, I worked for the UK Home Office just after that period and “tit-for-tat” is a lazy and naive response to the issues around human trafficking and other concerns we were trying to address in the UK. The response was obviously delayed by a lot of Brexit negotiation faff, but there’s long been worries about golden passports both within the EU and externally being used to wander in and out of the EU and Schengen.