They might have a dedicated fleet for some capacity. They might also have a less predictable encoding load (e.g. not be sure how much content they will acquire), or able to make trade-offs (encoding is expensive today? let's do a fast encode and wait until spot instances are cheap with the better one).
They might also be buying for different prices/conditions than what you and I see on the web site.
Note I'm not including their networking costs to get to the last mile, where they place a lot of their own boxes in ISP facilities pretty close to users, that would be about the same however they were doing core IT.
IME cloud _can_ easily be more expensive and more work than bare metal, in house or colocated. If course it depends upon the workload and the tools/resources available to manage it. Even with clouds there is still server management to do.
More work - definitely not. No matter how hard managing your AWS workflows is, bare metal will always be all that same work plus everything else related to hardware, cooling, power management, ISP and more.
Sure you have "hardware, cooling, power management, ISP and more", but that's all easy, especially compared to managing AWS workflows.
I've personally discounts ranging upwards of 90% for certain services and cloud vendors.
The arguments for cloud look different: services offered by the cloud providers, higher flexibility, no capex (though at small scale you can rent and at Netflix scale capex is presumably not an issue) or better scaling in highly variable loads.
Netflix encoding servers probably have very variable load since releases vary depending on season (like the flood of films for Christmas).
At one point it's quite possible that a combination of the two is the cheaper option.
And yes, you're completely right, load variability plays a huge role in all this.
- maintain the physical machines
- build or rent data centers
- have people to operate, maintain, upgrade the machines
- set up, build, maintain, update, upgrade infrastructure for your projects to work on your machines
All these costs are not insignificant when you need more and more machines. And as it was mentioned above, they don't do well when demand is variable: when you no longer need as many machines, you can't just decommission them. When demand spikes, you can't install new servers instantly.
On the contrary, there's probably decent product alignment with Gsuite (proven by Microsoft's acquisition of Github) & opportunity for Gitlab potentially getting acquired by Google.
Because overall this reads more like a sponsored post. Google probably offered a lot of money (good deal) to encourage them to move also.