Automatic startup on install is supremely annoying. There's a way to disable it on Debian at least, but it's terrible as default behaviour
Do you package all software by yourself? I mean, if the vendor-provided httpd package for example started and enabled itself upon installation, how would you structure your configuration packages so that httpd does not start until it's actually configured? Or (theoretically) if you needed to deploy a configuration change and an upgrade simultaneously and can't restart the software before the new configuration is in place.
I see this being rather easy if the vendor package simply puts the binaries in place so you can have your own packages run whatever scripts it is you need and depend on the vendor package, but I don't see how it wouldn't be a headache if the vendor package contained scripts to manage the service as well, which is what primarily annoys me on Debian-likes.
It is the *-conf package which depends on the application package, brings on the configuration and automatically (re)starts the application.
As a quick test, I installed httpd on my workstation, and it did not get automatically started or even enabled at boot.
I don't think there's anything wrong with using packages to control which software is running if you do it right, but I do think it shouldn't be default behaviour.