Roland Perry gurgled happily, sounding much like they
were saying:

Why _should_ something so relatively unimportant arbitrarily be the
single most important bit of packaging?

Because having dozens of different types makes replacement harder to
find.

No more so than oil filters, headlamps, tyres, windscreens. Should they
all be forced to be one of four or five basic types? How about front
wings or bumpers?