Considering I've yet to encounter some non-CPAN code (that is, code that actually runs solving some companies problem instead of just having the potential of doing so) that actually uses Moose, I'm not quite convinced about the "best-fit for most people" part.

I am the author of Moose so obviously I will be biased, but we have about 7-8 major production systems at $work that use Moose extensively to solve real world problems for some very large companies. Best Practical (RT, SVK, etc) uses Moose/Mouse in there new SD project and some of the Hiveminder API modules. Shadowcat Systems (of Catalyst/DBIx::Class fame) has deployed systems using Moose. I know that Moose is being used at ValueClick, IMDB, Yahoo! and Symatec to name a few. In short, just cause you haven't encountered it does not mean that it is not out there, because in fact it is very much out there. This is not to say that it is the "best fit for most people", even I won't agree with that statement.

What I do know is that Moose will get out of fashion and will be replaced by another system.

s/Moose/$anything_technical/g

In case you haven't noticed we work in a very "fashion" driven industry, this is just how it works. If you asked yourself that question before making all your technology choices (and weighted it heavily) then you would still be writing code with assembler on wire wrapped boards.