Water is a commodity (unless you live somewhere where water is scarce, where it may very well cost €1000/liter), software is designed for a specific function an

Water is a commodity (unless you live somewhere where water is scarce, where it may very well cost €1000/liter), software is designed for a specific function and is not interchangeable at random. If I purchase software to perform business function X, the value derived is from the function it performs for me, entirely independent of the cost and time required for you to create the software in the first place. If the software took you 5 years and €1M to produce, I as a customer will balk at any cost-plus price as my expected business value of using the software is say only €0.5M. But if you spread your costs over a hundred customers by copying (and maybe servicing) the same software, you can charge €0.1M from 100 customers, giving you €9M profit after your expense, and allowing each customer to derive around €0.4M business value. The value for both the producing and consuming side of the software was significantly increased simply by copying some bits :)