His people are the church. Jesus calls followers to be the body and He is the head. Yes, structures became known as the church but as you stated, they are not necessary for believers. Solomon built a home for God but their worship did not stop when it was destroyed. I do believe we were told to fellowship with one another with or without a church building. Church buildings probably became convenient. We are the church will continue on-line or wherever else God deems it so. I went to a historic colonial church but I know its days are numbered.