Comment by lossyalgo

I miss catalogs! And I'm not sure that works for every kind of product. You forgot to mention door-to-door sales (not a thing outside of the US AFAIK) or cold-calling potential customers (only applicable for certain types of products), good old word-of-mouth (need to get lucky and reach "influencers"), or throw tupperware-type parties. There are surely other methods as well.

Re: being careful

Any system created by humans will be abused unless regulated. And even then, there will always be loopholes which will be abused until punished (and even punishment might not be a proper deterrent if it can be calculated as a cost of business. (Yes I'm arguing for and against you, just thinking out loud basically ;)

edit: grammar