Just a caveat I'll add is that you have to work really very hard to build a system with equivalent/better durability and availability guarantees as the big cloud storage providers. It's typically not possible to be significantly cheaper with these same guarantees unless you're at large scale with well-established supply chain organizations, etc.

Of course if you don't need 11+ nines of durability or multi-datacenter redundancy, or if you have lower access requirements, then you can exploit those reduced requirements to your advantage.