He was in the right place at the right time and got lucky. Not through any competence.

Always switching technologies won't get you in depth knowledge, but it will show you different, possibly better approaches. I would say a bit of both experience, as well as learning new ways of doing things helps.

I learned Java at university. Inheritance and Polymorhpism were like black boxes until I learned Perl afterwards, and the mechanisms are there in front of you (OOP in Perl is a bit of a hack, but it makes it transparent how it works). That (and other features of Perl) helped my understanding of Java.

Being a good team leader and being a good developer aren't the same thing. You can be an amazing team leader but suck at being a developer. There are a lot of team leads that are team leads just because they got there first. I've seen one who struggled at basic problem solving.

However I get what you mean. The guy does seem to be a bit up himself.

Agreed, but he isn't good at that either!