As someone who was in sales and marketing for a manufacturer, and was subsequently involved in product development; on first glance selling replacement razor handles seem to be a terrible business model for a number of reasons.
First, my WAG is that the market and pricing really isn’t there to support the investment. The market for new razors and the replacement blades are where the cash lies. Although the OP would like a new handle, it just doesn’t seem to me that there would be that much of a demand.
This is important for two reasons. There has to be enough demand in order to bring all of costs: manufacturing, distribution, design, overhead, etc., down to be competitive. Without sufficient quantities, then you would always be stuck with higher costs than the manufacturer who could simply under price you. Great for the consumer, but your investors are left with the bill. Investors don’t like this.
The second reason that small demand cripples is fighting for the shelf space in retail stores. Large chains are extremely competitive, and places such as Walmart are cutthroat. You’ve got two weeks to hit a sales target or sayonara to your products. You need shelf space or you’re dead. Otherwise, good luck on Internet sales. It ain’t going to happen.
For pricing, according to Telemark’s research, a handle costs $5.50 retail. An unknown generic manufacturer needs to be at least 20% cheaper. Unfortunately for your investors, that retail price is going to be a moving target. If you start to chip into any sales of the manufacturer, they can price you out of the stores. They will have significantly larger sales, so all of their costs are less. They already have contracts with the factories and cheap rates on the container ships across the Pacific. They already have distribution to the stores in place.
The next major problem is as was pointed out in the OP, the various handles don’t match the blades, so you have to have an equal number of handles or some sort of system of adapters, which increases your per unit overhead.
Then another problem is that you will always be a step behind the razor manufacturers. They can bring out new models which will require you to make changes to your products and stick you with a bunch of obsolete handles, for which you’ve paid.
This is fundamentally different than a market for generic ink, for example, in which printer manufacturers need to maintain interchangeability of the ink cartridges among their models.
My experience was in a professional market, and not retail, so some of the assumptions may not be exactly right, but it doesn’t seem to be an attractive business model.
