When I was in I can remember reading WT commands not to use the brothers and sisters as an opportunity for business ventures.
I guess in hindsight it was because the WTC was already doing it and didn't want competition for the resources of income being limited. In addition to buying all your own literature and magazines, who else remembers the book covers, notebooks, bookmarks, etc sold at conventions with the assembly theme stamped on the front in gold coloured lettering?
Nowadays people claiming to be jws have oodles of websites selling all manner of goods to them, many infringing the JW logo. They must have lots of JW customers or I guess they wouldn't be making enough profit to continue. How times have changed!!