Coming up with a great idea is the easy part. It is the execution of bringing your idea to market that is the hard part. I have run into many clients who have a great idea, around which they want to build a business. When I mention that they can license the product to a manufacturer and get either a one-time lump sum payment or a royalty of say 2-10% for minimal risk, most say they would rather get a bigger share of the pie and build their own business around their invention.
However, starting up a manufacturing facility is not cheap or easy. It requires considerable skills that the fledgling entrepreneur most often does not have. Assuming they tackle the manufacturing facility, have a handle on quality control issues, and have properly priced their product, they generally have no distribution channel with which to get their product to the public. Most retail stores prefer to work with large distributors with a huge catalog of products rather than thousands of small manufacturers.
Selling online means lots of shipping and handling costs, as well higher customer acquisition and logistics costs since there are no bulk orders. Spikes and lulls in sales create order fulfillment and carrying cost issues, and then there is customer support and return order processing. Furthermore, you have to pay commissions if you sell through online stores. If someone rips off your idea you have to enforce your patent, which costs more money. In the end, the inventor is often much better off inventing new stuff and selling their ideas or collecting royalties rather than trying to become an entrepreneur.
Are you really an inventor who mistakenly thinks they want to become an entrepreneur?