Ruby gems security issues: Have hackers lost their interest?

Security issues on rubygems have decreased over time, from 93 in 2013 to 8 in 2017 (expected).

Is it because ruby programming community has gotten more mature? Are developers better? Or is it that hackers and researchers have lost interest?

Whatever it is, here you have the numbers:

*data from https://github.com/rubysec/ruby-advisory-db