Damn, the Alphine linux ISO is tiny
With tons of packages available (with patches and live maintainers). With formal stabilization process. With well tested package management system (with hundreds of bug fixes in 20 years of use). Which can be used as host and as container (so you will need to learn well and support just one OS). With Systemd, which handles daemons well. With well supported LTS version (RHEL/CentOS). With option for paid support. With glibc, which is much faster and feature-richer than musl.
Why I should use Alpine, which cannot even handle versioned dependencies between packages? Literally, I cannot tell that package A needs package B >= 3.x or package C < 2.x, which causes serious troubles in complex systems.
I was impressed with Atomic's size, but seeing how much smaller Alpine is, I can't help but wonder what all the additional size is in Red Hat's images.
If Alpine did what RHEL does out of the box it would be hundreds of MBs as well.
However, if you'd like to craft your own minimal Atomic host, you can.
Making minimal containers is pretty easy, though, since yum/dnf lets you create execution trees that contain only what's needed for an application to run (as others have mentioned).
So, really, doing micro-services on RHEL/CentOS/Fedora hosts is pretty easy.