Regarding PHP versions, this is a more relevant link, showing how old and outdated older versions of PHP are:
https://secure.php.net/eol.php
However, I have many clients on various hosts with locked-in LAMP platforms, older unmanaged VPS servers, licensing issues, and tons of other reasons why their website is still hosted on some outdated version of PHP, and a plugin shouldn’t up and break their website one day, when there are ways to code around older versions of PHP, at a minimum exiting when not running under the required version of PHP.
Upgrade your PHP, yes, but code plugins not to break sites one day, too, especially when it’s used on tens or hundreds of thousands of sites, and so the number of broken sites can easily be in the thousands.