Just to build off this a little, there are also quite a few examples of cases in which Apple "sherlocked" an app and the original app(s) continued being success

Just to build off this a little, there are also quite a few examples of cases in which Apple "sherlocked" an app and the original app(s) continued being successful as they offered a much more advanced feature-set than the basic version Apple introduced. In some cases app authors talked about getting more publicity as the feature or utility became more mainstream and more people searched for functionality that wasn't available from Apple.