You'd never see a Windows developer work in MacOS or a iOS developer work in Linux but Linux developers (server side) routinely work in MacOS

Unnecessary abstraction

Counter-argument: it could be risky to dev on and deploy to a single monoculture.

But empirically, I've been developing on macOS (etc) and Linux (often simultaneously), and deploying to Linux (Debian, RHEL/AL), Solaris (etc), and FreeBSD ... for more than 20 years.

Aside from package management tooling differences, package naming, and package content splits (e.g. pkg vs pkg-dev) -- all of which are equally inconsistent between Linux distros -- I cannot recall a single issue caused by this heterogeneity.

> iOS developer work in Linux

I dream of the day Apple releases official docker images. Building for iOS is the only reason I have to touch a Mac.

All SNES games should have been developed in Mario Paint or it was an unnecessary abstraction

Define "unnecessary", please.

> [...] or a iOS developer work in Linux

In the past I did a lot of successful work on iOS apps from a Windows system, thanks to Xamarin and a mac sitting on a shelf, acting as the remote system.

Also, please, remember what "cross compilation" mean.