EDIT: Okay so! I made a claim that Figma embedded a PNG in an SVG and it is possible that what happened was a designer put a raster image into figma and then the engineer who exported this assumed it was built from individual elements. It looks like if you group non-raster elements and export SVG it will give you a zip with a single, non-exploded-into-individual-layers SVG file.
My mistake, once again bitten by people not using Figma how Figma wants you to use it
@darius I found this out a couple of weeks ago, I was so cross. Just don't offer it if you can't do it!