I think it is pretty much all marketing. Just like buying ice fishing line, smaller spool less yards of line greater price, just print ice fishing line on the label and charge more. I always make my fluoro leaders off of a big spool of line. I normally figure the bigger the spool the less cost. If I can I try to buy min of 500 yard spools of my favorite line, the single reel fill spools are a rip off price wise.
Give a man a fish he will eat for a day, teach a man to fish and he will sit in a boat all day and drink beer.