Today I want to write a little bit about the difference between building things in real life and in Second Life.
Building things in real life, for example a simple chair, can be hurdlesome. First you need the materials to build it, namely wood and at least some glue. Second you need the right tools to achieve your goal. Third you need knowledge and experience how to do it and a certain amount of time to actually build one chair. The more chairs you build, the more time you need. Please notice, that the important fact is that this is linear. For example, if you need in the average 45 minutes to build one chair, then you would need 7*45 minutes in the average to build seven chairs. And last, but not least, if you never build a chair before, you need to make some research first actually how to build it and of course the time it actually takes to build it has also some value.
How to gain profit of it? Well, you must reach the break even point, of course. Only if you have reached it actually you are making profit with your good; if you never reach it, you will make only a loss, plain and simple.
Since SL is virtual, we are now in the wonderland of software production (actually the same rules applies to other software, e.g. Windows from Microsoft). Costs for building materials and tools? None. It's all in the client, Luke. Costs for building many products? None, it's just simply copying on the server in a fraction of seconds. It doesn't matter if you actually only sell one or one million pieces of it. So what costs are left in SL to reach the break even point for a product? Simple: research and labor costs.
So if you do it right, it's actually from this point of view easier in SL to reach break even. But, and please consider this also, the potential crowd of customers is in SL of course drastically smaller than in RL, so you need some to make your product popular by all means. (All of this does not always apply to custom builds, of course.)
And this is also how Microsoft makes so much money with Windows. Actually the production costs per unit are constant low (burning DVDs is mostly automated, anyway), the research costs are constant and only happened once, so it's easy to turn it into a cash cow, when many people buy it.