IMHO, the rules that qualify someone for an AS number should qualify them
for a prefix. It need not be a truly long prefix, but larger than a /48.
I agree with the first part, but, a /48 is 65,536 64 bit subnets. Do you
really think most organizations need more than that? Or, by larger than
a /48 did you mean a longer prefix (smaller allocation/assignment)?
The important part there is "most networks".