Glomung is right.
But let's say for a moment that there are extreme cases where the bread and wine aren't present (like a war zone perhaps or in areas where the resources are just so scarce -- though even in those areas they often are made available), that usually meant no substitute would even be available IF substitutes were permitted. Because substitutes aren't permitted, it isn't even considered.
May I suggest that people google the actual facts to see where the wine producing regions of the world are. The world maps clearly shows that the wine producing countries are very very limited, and that their vine growing areas are even more limited. Not only that, but many of those wine areas are comparatively modern developments, ie. California and Australia.
Today, mass exports do a good job of distribution around the world, but in previous centuries such exports were prohibitively expensive luxuries, which were only affordable by the ruling classes. Wines made from grapes were clearly
not commonly available, as they were in Israel.
Jesus used wine as a metaphor for blood because it was the common beverage for that area. Wine, often diluted, was regularly drunk in preference to water because water was frequently too dangerous. Fermentation killed bacteria etc.
"Because substitutes aren't permitted......."
Substitutes might not be permitted by your church and many other western mainstream churches Lysander, but that's where it stops. Too many seem to be limited by their own tunnel vision, without considering those who are outside that landscape, who have never seen things from your convenient western perspective.
As mentioned previously, I was in Nepal, high in the mountains on an illicit mission where there was no wine for hundreds of miles. That happened because it is a tropical zone and grapes don't grow anywhere near, nor were there any shops for many miles.
I was visiting a christian village well off the beaten track and they regularly met for worship and communion together, with tea and rice cake. To deny them this freedom, based on a western legalistic understanding of wine and bread seems to be very sad indeed.
To prohibit communion to these people, until wine can be efficiently imported, is utter nonsense. Our spiritual walk should never be controlled by whether there is an effective commercial network available.
I am not in any way rejecting the use of wine and bread where it is the norm, I am just trying to burst the bubble of nonsense which surrounds taking communion. We have no right to tell those who don't have easy access to wine that they are wrong!