Mac OS does some amazing things for security. An immutable root OS, sandboxing, very user friendly disk encryption. But there are certainly decisions that hold back the platform. Their business decisions have driven most developers away from the App Store. There is a notarization process, but it imposes a burden that many small open source projects can not bear. They don't have an easy way to run untrusted software in a containerized way (compare Fedora toolbox). Installing things globally via homebrew or a random install script is still the way to go.