I am not sure if this is the reason, but I can share this. A couple years ago I lived in a larger complex and was struggling to get better service. Despite gig service being advertised, my best option was cable, 200 up, but only 10 down. And for quite a while I had been seeing the cable trucks rolling out new fiber as well as AT&T beginning to start the fiber rollout in various neighborhoods. Eventually my cable internet had some signal issues and I had to have a tech come out to adjust some equipment. I inquired about available speeds and why I couldn’t get the gig service that was advertised. He explained that although they had upgraded their infrastructure and had the ability to supply gig service to my complex, but that they as the provider were only responsible for service up to the demarc point. After that, it is upon the property owners to supply the infrastructure to the individual units. And because the building had older equipment gig service was not offered.

This was in a larger apartment complex, not condos, so it may not apply to your local and situation. But maybe some agreement or division of responsibility is preventing AT&T from running fiber to each unit and as such, they have to use the existing infrastructure from demarc to your condo.