As a PHP developer, merging the PHP repository into core will be disastrous for me. I have 27 packages installed for PHP 5.5 - 7.2, and the versioned extensions will evaporate. So much of my tooling is built around homebrew and the `homebrew/php` tap, that my entire toolchain for development will change.
The last time, Apache was switched from installing/running at the system level to user-based. That broke almost everything on my system for a day while I tried to fix it. Worse, there wasn't a warning prompt before the package upgraded.
I don't have time for things to break down every 6-12 months.