In short, yes it is.

The concept of having a predictable recurring bill, and known costs can have a lot of value. In the opex hardware model, there is usually a hardware refresh built in (a lease of sorts) and also covered replacements for any failures before the refresh.

> a predictable recurring bill

This makes no sense to me, because almost no OpEx-based services operate on a predictable billing model. Usage based pricing means they are subject to change.

If I buy a $5,000 server, and it lasts me five years, I can plan around needing $1,000 a year set aside to replace it. Meanwhile, my AWS bill can suddenly be $20,000 with no warning.

The hardware refresh model you describe... I've actually only ever seen in a CapEx appliance, where paying for the support contract got you those refreshes regularly, replacement for failures, etc. but had an initial upfront purchase cost.

When the news comes out that a major company has signed a deal with a cloud provider, it's that they've committed to spend $X over N years. Presumably the deal would be renegotiated if their usage changed dramatically, but it is not actually variable pricing.

Compare SaaS to COTS software: same thing, (somewhat) different industry.