Did you factor in the resilience and redundancy S3 gives you and you cannot opt out from? I have my NAS, and it is cheaper than S3 if I ignore these, but having to run 2 offsite backups would make it much less compelling.
They probably factored RAID1 into that price, which you can skip if you're setting up three copies. (At least I hope they did, their hardware prices must be dire if $2000 only gets you a tiny NAS and two 10TB drives.) If I do napkin math based on US prices, a mini PC and a 20TB external drive are a bit under $500 total, and a 2 bay NAS and a 20TB internal drive are a bit over $500 total, so that's about $1500 for the triple-NAS option and $3000/year for the S3 infrequent access option. Still extremely compelling.
Yes and no. I have been using NAS for a long time, and I use older drives as offline/offsite backups. So the cost is mostly amortized already. Those machines are off except once a week (local)/ once a month (offsite), to do an incremental backup. So this is a good use of some older drives.
