Matt,
I'll have your back on this one. I recently made a carving that I molded and will then try making resin copies from (I'm new to the process so I'm slowly learning how the costs add up). The material (Smooth-on) to make the rubber negative mold cost me $150 alone! The resin mix to make copies is at least $25 for two small bottles....and you need more of it for bigger pieces, which is more money.
Then you need to make copies. Then there's the touching up/finishing which Matt mentioned. This is A LOT of work, and takes a considerable amount of money and time. Oh, don't forget waiting times for curing, measuring materials and a lot of refining. I'm repeating Matt's points because he's right.
It may look easy to make for many of you, but it's MUCH harder than it looks and it's not cheap! It's not like stamping out Christmas cookies and dashing sprinkles and icing on them. You're doing it the right way, Matt. Carry on.