reasons for modperl declines?

For me I run several apps on mod_perl, including a AI prediction app 
which costs heavy CPU/ram. These apps run for long time and behave just 
fine.

Today it sounds very few people use mod_perl for development/deployment. 
I think the main reasons may include,

1. perl for web development is somewhat out of date
2. mp lacks threads support
3. lacks a modern framework (rails like)

And others? what's your thought?

Thanks

-- 
regards,
Jeff Pang