Good luck with APT pulling in Qt and GTK packages on your headless server.>>21211>Most companies use RHEL
Yes, because they can pay someone to manage it for them. For companies is important that responsibility/risk be mitigated/offloaded. For example, if your service is unavailable due to a problem with your OS, and your OS management is outsourced to some RHEL corp, then the fault and therefore liability rests with them, and your customers cannot ask for a refund because the disruption happened through no fault of your own. Why RHEL? Because it is an established foundation that already has all the training and certifications in place so it is easy to train or hire the right people. Ubuntu has done the same, that is why Ubuntu Server is also popular.
I'm sure Slackware servers/hosting/infrastructure exist, but it is probably done in-house and for historical reasons. I'm sure there are fewer of them now, ever since RHEL and Ubuntu became solid enough to actually use.
For a server infrastructure you run yourself Slackware is perfect. There are no "automatic updates". You don't just click through the info box to install the latest updates. If everything is working, then your computer does not change between shutdowns and reboots. The updating is done by you and only of the programs you wish to update. If the only change between versions of a program on a headless server are Wayland/X bindings, then why should you update and risk potential problems when you don't need those Wayland/X bindings?
Where companies relegate OS/package management to a company like RHEL, you, by choosing the same tools, are relegating those responsibilities to potentially hundreds of random people. And you have to trust that when you do apt-get update && apt-get upgrade your system won't break.
Speaking of systemd, look at all the shit systemd does at boot, as PID 1, with a 3m wait for a service to come up before moving on. If you're managing a server remotely (without that fancy server management hardware that allows you to see the status of a machine remotely) it could take 20-30 mins to boot. If it boots at all. With slackware, there is no mystery what is going to happen after reboot.
I'm starting to think there aren't that many adults on this website who know how the world works.