That's my point. Commuion was a shared common meal. Baptism was for adults not infants. There wer no idols or statues. The believers not only worshiped but shared what they had together. Not just in words but tangible items too. And the churches sent people to other churches to learn and edify each other as well.
As far as I know, the movement that calls itself 'Reformed' has historically not tended to be into statues or even that much church art. Some of them were against decorated altars and clerical vestments. It was less ornate that Lutheranism. I don't know about now, but that is probably still true to some extent. Those in that movement can correct me if I am wrong. Movements associated with Calvinism and the churches in Geneva Switzerland in the Reformation era often call themselves Reformed. Presbyterians and Dutch Reformed are from that movement.
Historically, many of the Baptist groups had theology in line with Calvinism, but much of the movement moved away from that. In recent decades, some Baptists have called themselves 'Reformed Baptists.' Since those who historically called themselves 'Reformed' have believed in infant baptism, Baptists calling themselves that must seem strange or comical to them.
I agree with you that baptism is for those who have faith. I would not say it is for adults only since children can believe and confess their faith. Early in the Reformation period, some of the anabaptists claimed to be prophets, led a rebellion and led people to their deaths. Some started practicing polygamy. The very peaceful anabaptists got blamed for it and anabaptists were considered to be dangerous. So those on the other end of the argument polarized against infant baptism and persecuted them. Infant baptism is such a very, very old tradition and it was not specifically addressed in scripture. Lutheran and Reformed movements weren't
that by the book when it comes to such doctrines.
As far as why didn't they go all the way back to the apostles? Well, if you ask some Reformed people, they will say they did. I would agree that it did not go all the way back to apostolic practice in a number of ways. I agree the early church ate an actual meal. A cracker and a tiny portion of wine might be a full meal if you were very poor, btw. I don't see the micro-portions as forbidden. It's a practical solution to prevent the gluttony problems of Corinth, but it's probably overkill that probably deprives us of some of the experience and makes it hard to make the connection between the supper and its historical roots in the last supper and the Passover. Historically, the Roman Catholics got rid of the wine for nonpriests and gave them only the tiny wafer.
I would also point out the mutually-participatory nature of New Testament meetings. Hebrews 10:24-25 indicates that when the church meetings, we are to 'exhort one another'...in the context of provoking one another to love and to good works. I Corinthians 14 contains 'commandments of the Lord' for church meetings. The type of meetings the church was assumed to have was a meeting where 'every one of you' sings, teaches, shares revelations, tongues, and interpretations. The commands there allow for interpreted tongues, for prophets to prophesy, and for 'ye all' to be allowed to prophesy. The Bible never tells 'pastors' or even elders, specifically' to preach or teach in church. Elders are to be 'apt to teach', so if 'every one of you' may teach in church, we can infer that those who were to be appointed elders in the church were to be among those who taught the assembly.
The implication seems to be that there was a somewhat 'open floor' in the church. Edersheim's 'Life and Times...' indicates that regular men in the synagogue could preach in the synagogue. in Acts, the synagogue ruler asked, "Ye men and brethren, if ye have any word of exhortation for the people, say on." The church seemed to have a more 'open floor' than the synagogue if Edersheim presents it accurately. But the synagogue could have also had a very open format, too, to allow Jewish men to speak. Some men opposed Paul verbally in the synagogue (Acts 18:6). It is possible that Paul and Barnabas argued against false teachings in a church meeting (Acts 15:2.) Apparently, the Jerusalem church allowed members to speak on a contraversial issue during a church meeting (Acts 15:3-4) also.