A question just for fun:
Because of the dangers of drinking water, wine was a common drink in the days of the New Testament. Sure, maybe most wines were heavily watered down, but wine was still a regular drink. Likewise, bread was a common staple at tables. Cheap, easy to make, and filling. When Jesus taught the disciples to remember his blood spilled and body broken, He used the bread and wine which, yes, were part of the Seder meal, but also possibly the two most common food products of the day. Nothing special about them (outside of the symbolism they provided during the meal).
My question is this: Rather than creating a liturgical ceremony to be carried out weekly, monthly, quarterly, annually, or rarely, because of the common nature of what He used, because wine and bread would be a regular thing at the dinner table, could Jesus have been telling his disciples "Any time you eat or drink anything, think of what I have done for you." Did He intend it to be a sacred thing or a daily lifestyle thing?
That said, flash forward to today. Wine and bread are not as common on the dinner table now as they were then. Depending on the church and denomination, observances of the Lord's Supper, communion, sacraments, etc., utilize many different ingredients. Some use wine, some grape juice. Some unleavened bread, some leavened, some wafers, some chalky little cracker type things. I have known a church to introduce preschoolers to the idea of The Lord's Supper with Kool-Aid and Goldfish crackers. I could see using Dr Pepper and Doritos for teens.
If we are going to insist on it being a specific kind of element and nothing else will do, I can see that treading close to idolizing the element. But, at the same time, using certain items and only those might be observing a sacred commandment. Which would mean those churches using anything besides wine and pita bread are guilty of not observing properly. Perhaps Jesus' instructions were more about the remembrance than the ingredients. But then one must contend with Paul's admonition to not take part in the Lord's Supper unworthily.