Two questions: Can’t we have sacrifices without a sanctuary? Can’t we have a sanctuary without sacrifices?
Sacrifices without a sanctuary are certainly possible, at least in theory. But the Torah frowns on the idea, and for many generations after the people entered Israel there were constant warnings about building altars all over the place.
Chief Rabbi JH Hertz said at the time of the Balfour Declaration that a people can live without a land, but a land focuses its people. The same can be said about the sanctuary. Sacrifices can happen without a sanctuary, but the sanctuary focuses the sacrifices. You can pray anywhere, but praying in the synagogue has its advantage: the building enhances the thoughts and emotions of prayer.
Can we have a sanctuary without sacrifices? Technically yes, but what’s the point of a empty shell without activity?
Travel the world today and you see the remnants of old synagogues which now have no community, no services, no purpose except as museums and mausoleums. Those buildings were mostly the victims of a rapacious enemy: we have to make sure that in places where there are synagogues and human beings, there is a connect between them.
Jews who bypass their synagogues are doing very little for their posterity, and very little for their own souls.