I live in Germany, and the English language media is reporting the Austrian decision very differently to how it actually is.
First of all, German-speaking countries have had "3G" ruling for months - that is tested, recovered, vaccinated (all start with G in German). Recovered or vaccinated people show their medical certificate to access eat-in at restaurants, gyms, leisure activities, events etc. If you don't have a certificate or don't want to show one you can show the result of a rapid test from a rapid test centre (which are available everywhere and free). Children under 16 do not need to meet any of the conditions, even though vaccination is offered from age 12. Teens can show a school ID to prove their age instead. Masks have remained compulsory pretty much everywhere and there has never been any medical exemption from mask wearing. Also it's been surgical/FFP2 only for almost all of this year.
Essential services including shops, public transport, takeaway restaurants, medical treatment (including non-urgent), schools/classes etc is always accessible to everyone. Employers are not allowed to ask an employee's vaccine status.
It was always possible to meet people in private, indoors and out, up to a max number of households. Adults in a relationship are considered one household. Children of separated parents are considered members of both households. Vaccinated and recovered people just don't count towards the total.
During the strictest parts of lockdown shops were reduced to "essentials" only and schools/childcare was closed, but they aren't proposing to bring that back.
Moving to the 2G model means removing the testing option for anything non-essential, so certain shops, leisure facilities, gyms, hairdressers etc. It's certainly not "only go out for food and work" whatever the media is saying. People who have a medical reason not to be vaccinated, including pregnant and recently pregnant women (even though this is now considered safe) can still use a test to access those services. But even someone who is unvaccinated and has not had covid can still do most things.
I don't know what they are tying it to in Austria, but in Germany it's tied to how full the intensive care units are rather than case numbers in general.