basically they build their own hardware: https://www.netflix.com/openconnect

you can't put your own hardware at AWS.

they are the poster child for using AWS for what it is good for, general purpose compute (storing your play list, the list of all movies, controlling the CDN etc)

but I imagine for streaming you need bare metal

They're actually one of the most prominent companies with a large deployment of FreeBSD (the OS they use for their CDN).

https://www.netflix.com/openconnect/software