I can't imagine the infrastructure to do it is trivial, but I would say the larger burden is network effect. Bandcamp has existed for a long time and I know of indie record labels who use it as their default distribution. I am aware there are indie alternatives (some of which provided in the comments to my first comment). Also disruption of service often results in loss, would someone who is no longer focused on music move there stuff over if things changed dramatically? Would people download in time, etc?

Obviously this is all speculation, bandcamp could continue on as it has been for the conceivable future, but I am less pleased about that future than I was before I saw this news.