Theoretically, you're correct. In practice, you look at a company like Amazon (where I work) and our software, while mostly it is written in Java and other high level languages, there are many bits and pieces written in C and C++, and even the high-level bits are likely to fail spectacularly if you try to run them on anything other than a close relative of the Linux distribution they were built for. This is just a fact of software development. Write-once run-everywhere is a virtual myth.
Unless of course you're talking about building a single Linux virtual machine image and deploying it to thousands of servers. That actually works phenomenally. Doesn't work as well with Apple's software. Or Microsoft's for that matter (though this is largely a question of licensing cost.)
https://www.neflix.com https://www.amazon.com
And we're not the only people making consumer-oriented Linux software. For example, https://gmail.com .