Yep, open-source is 'free' as in puppy. The TCO of open source software is not zero. It's just that some people are willing to absorb those external costs.

When I, as a developer, have an issue with some open source code, I spend some amount of time fixing it (labor cost), and some amount of time with a broken system (downtime). But it's not a big deal for me, if I spend 30 minutes troubleshooting a problem. Scale that up to a company with thousands of employees, and those can be big costs.

And of course, as we all know, you'll never spend any time troubleshooting proprietary solutions.

I’m not saying that proprietary software doesn’t have support costs.

I am saying that source code licenses are irrelevant to support and operations costs.

Both RedHat and Microsoft will sell you a support contract.