Another trick in software is to avoid rewriting the software by using a piece that's already been written, so called component approach which the latest term for this in the most advanced form is what's called Object Oriented Programming.
There is this thing called the GPL (Gnu Public Licence), which we disagree with... nobody can ever improve the software.
A great lathe operator commands several times the wage of an average lathe operator, but a great writer of software code is worth 10,000 times the price of an average software writer.