The remainder soap creates a valuable commodity at a small cost of the original, but hotels (or their toiletry suppliers) aren't solving this on their own (a potential revenue stream).
How do we connect the dots?
I say this as US jurisdictions are cutting (resident paid) recycling programs because of the high cost of sorting plastic; while the US experiences cardboard shortages, metal shortages (as old vehicles waste yards) - in the midst of climate change pacts.
OR, as few jurisdictions implement composting programs where 40% of landfill waste is likely compostable. (and there is a market for curbside compost companies, where consumers are paying $40/mo though the output is very valuable)