This is an open letter to all my fellow programmers:
Don't lock yourself to one single platform, no matter how good or enticing it is.
Specializing yourself in one area is great. Being narrow-minded and ignoring everything else is setting you up for failure.
One thing is being specialized, another thing entirely is only working on one platform while ignoring and refusing to do anything else. If you don't want to learn new things you might want to reconsider your career choice. Tech is always moving and changing. What is best now, might not be in 6 months.
Even if the platform you're developing for will last 50+ years (unlikely, but possible), you're going to miss a lot. All your decision will be based on your limited point of view and lack of knowledge.
To make an example: You're making a mobile app if you've done a little of backend developing you might imagine how the database could look like and you could better structure your application.
Opening your horizons on new tools, languages, and methodologies will make you a better programmer. Every single community does something a little bit differently.
If you're doing iOS in your day job, do something else during your free time.