"too much duplicated functionality" What should that be? Who decides when its too much anyway? No one cares about duplicated functionality in stuff they don't use. Probably 90% only want to download form YouTube. So why would they care if part of the code is used in another downloaders they don't use. If you create a kernel/OS/Distro sure you don't want duplicated functions but this is just a downloader tool. Also if there are generic functions that can be used by different tools you create a lib. No one has to reinvent the wheel. Would it cause more work if summed up? Yes most likely but the work is shared and independent.