So if we apply your logic to software, a "thoughtful R&D process" of yearly releases (also known as "waterfall software development") is better than agile process of shipping frequently and tweaking your future features based on customer feedback.

Etsy (http://codeascraft.com/2011/02/04/how-does-etsy-manage-devel...) and just about any web dev shop disagrees with you.

There's nothing different about hardware.

In fact there's a story about a guy who build human-powered airplane not by planning harder but by increasing the frequency of iterations (http://www.fastcodesign.com/1663488/wanna-solve-impossible-p...).

This is exactly the idea behind Xiaomi's hardware and software efforts: improve faster by learning faster from more frequent iterations. Apple can only learn if their stuff works every year. Xiaomi can learn something every week.