Look at the price of a regular SAN with regular disks. It still can't compete on price! I did a price/performance comparison of a single MSA70 (25 disks) to an EVA3000 - it was 8x cheaper per MB/s. And that's a really cheap EVA. As you move to bigger SANs, the cost per MB/s gets higher still - they're not designed for high performance service levels to an individual server.