Here's my guess, I think the machines that make most of the wrap material are old & the 54" wide material from machine was standard. Some companies use some old machines when large production is not needed, the cost of new machines would take lots of orders for the larger size material to pay for it, some of the candy makers still use very old machines.
I just did a quick Google search: apparently there are a lot of different industries that use 54", in length or width, as a standard in some sizes of materials they produce. Must be a commonality among different rolling, stamping, cutting machines.
Here's the skinny: wrap material - usually pearls and such - actually starts out as a solid block that is indeed made in Italy but is used to make eyeglass frames. 54" works out to be the optimum size to yield the maximum number of frames with the least amount of waste. What Delmar and other such companies do is take this solid block and slice it thin and apply a backing sheet to it. This material is also used to make guitar picks and decorative elements on accordions. Sparkles and glass glitters are layered between a tinted sheet (i.e. green, blue,. etc) on the top and a backing sheet on, where else, the back.