The performance improvements along with the support policy should hopefully encourage many sites to move to PHP 7 within a year; PHP 5.6 will be unsupported in 8 months (though it will receive security fixes for another year).
The recent releases of Magento 2.0 and Drupal 8.0 should help move more sites to modern versions of PHP, but there is a lot of work still to be done on contrib modules to get full functionality out of M2 and D8