"Let me ask you a question. If I were to suggest that we add a hamburger and a shake to the Lord's supper, what would you say?"
Me? I'm not a Christian, so I don't partake. However, if you examing the scriptural basis for that sacrament, it's pretty easy to see that Jesus himself described it. He did not say "Eat some food and drink some beverage in remembrance of me." His words were much more specific, and have been followed down through the years.
There is an enormous difference between the specifics of the bread and wine of communion and Paul's letter where he says it's a good thing to sing as part of worship.
Dogmatic prohibitions that are not strictly defined in scripture are probably not worthwhile. The example of the use of instruments in music is one such. If only to keep the congregation in tune with each other, musical instruments are useful. An a capella congregation is usually not all that musical.