Business whether online or offline is really tough. It would seem that going online would be the cheaper way to go because you don't have to have the same things as you do in the offline world, such as building, electricity, plumbing, insurance and the list goes on and on and on. Online all you need is hosting, autoresponder, email and a way to get online.
I have a successful offline business, but online for me has been/is tough. One reason is competition. Everyone wants to make the buck and the internet makes it cheaply to do and there are so many people out there trying their hand at business.