I could see something similar to this working well when a subscriber's ISP hosts the actual OS instances. There are a lot of benefits to having professional administrators in charge of systems, something extremely rare for home users. Given adequate throughput and low latency to the data center, less computer savvy people could connect to these managed instances, which are provided by their ISP. They wouldn't have to know about or care about updates, virus scanning, or even backups for their data. ISPs would (potentially) have much lower rates of help desk calls.