Yes, but with pay-for-software model, I have the option not to upgrade. That may mean that I am not covered by warranty any longer and cannot get support for my version, but a) I can still use it and b) if the company goes under I'm not scrambling to find an alternative. It seems to me that that PaaS and SaaS have a customer trust issue. You have to believe the company is rock solid or the company has to have some sort of escrow account to ensure operations for a period of time if they are failing. At least with IaaS, most of it is virtualized and you can hopefully move your image to another provider in minutes.