This is not true. People who copy will mostly do it for money. Finally the passion for the idea trumps the desire to chase money and your product will eventually suck. On the other hand if you think you can make a better product from existing solution, then there is a good chance of you succeeding.
You can try copying any one of those of ideas for money and see for yourself.
You can try copying any one of those of ideas for money and see for yourself.