People can copy the source, but they cant copy the top download count, or a reputation as a good developer or company. Once you have loyal customers and a reputation there is no point in hiding the source code in my opinion.
They can copy your code, but they don't understand it like you do, and therefore can't provide the same level of support or quality in updates. If they copy your code and make it closed source, people won't trust it, and if they copy your code and make it open, you can just steal changes you like back again.
They can copy your code, but they don't understand it like you do, and therefore can't provide the same level of support or quality in updates. If they copy your code and make it closed source, people won't trust it, and if they copy your code and make it open, you can just steal changes you like back again.