I would agree that the current adoption of raised beds (RB’s) by a lot of new gardeners is a fashion, and some people put them in because they see them on TV or other gardens without any thought as to why they are doing it.
I would struggle to have them on allotments except in special circumstances like really bad drainage or maybe for specimen Leak growing.
But there is more to them than just modern fashion.
There are many examples of medieval gardens that had small wattle fences of about 6 inches high that created the divide between path and the cultivated area to create "No tread/dig" beds, by common sense if the idea is to never tread on the cultivated soil, it would tend to create beds of about 4ft across, and the length would want to be between 10 and 20 ft, too short and they are unpractical, too long finds you jumping across instead of walking round hence the standard modern shape of RB’s.
I accept the reason for no dig beds was far more important in the past for the simple reason of; "You try digging a plot with a wooden spade". Anything larger than a garden by a cottage or castle/monastery courtyard would have been ploughed, but ploughing with horses needed strip fields, so not normally done in smaller areas, hence gardens, hence no dig. Even Roman gardens would have been in courtyards and no dig even though they had slaves.
I would guess that historically no dig beds are far more traditional than the “Standard” way of allotment/vegetable gardening seen for the last hundred years. I can’t see a Neolithic, Bronze age, Iron age, Roman British peasant, Anglo Saxon or Medieval gardener is ever going to tread on his precious dug over soil if his shovel is a Deer antler, or wooden spade, and it’s really only the later part of the industrial age when people were leaving the land that a modern metal spade became a reality for an average peasant (Most of the population).
In other words, once man found agriculture some 10 to 20 thousand years ago and stopped wandering from site to site as a hunter-gatherer he would probably used no dig, if soil isn’t trod on every year and worked in traditional ways (Adding compost) the soil level will raise up and you end up with RB’s, then to keep it tidy you add fences or boards and you end up with the modern RB.
To my mind the principle behind the no tread/RB approach has a lot more going for it than avoiding digging, increasing the fertility of the soil would be the main idea; there are other reasons for RB's.
1 Some people will be daunted by a large area of soil to cultivate and often not gardening because it gets on top of them, by working a series of smaller beds, they can keep up with the workload and feel they are getting somewhere.
2 Using raised beds with a light and open soil makes gardening easier. This is useful for all sorts of people.
3 By working smaller areas with a lot more control, you increase your yields for a lot less effort, also you need to practice much more discipline over what and how you plant, no more 30ft long rows of Radishes. You hopefully micro manage your beds to maximum yields for what you can eat at one go.
I am sure I could find more reasons, I am sure others could use loads of arguments for not RB gardening.
Some of those arguments could be along the line of too much space wasted on paths and the waste of the wood, and this is probably true especially if someone makes the paths too wide, or uses wood when there just isn’t needed, but by the time you take out all the paths on an average allotment plot I doubt if the waste area is that different.
I am sure your friend with his 4ft paths is just a fashion follower, not really knowing what he is doing, I doubt he will make much money from his garden, then no one in a modern economy will, far easier and cheaper to go to a supermarket, but that’s not why we garden, otherwise we wouldn’t spend money on greenhouses, rotivators, cars to get to an allotment (If you think an RB is silly, think about owning a car to collect your vegetables).
So it comes down to fashion, pleasure and choice. Is that a problem?
Bob