When I work with companies migrating to the cloud, we always cull through their application and data to determine several factors. First, should we rehost the application (lift and shift) or refactor the application (rewrite pieces for the cloud platform)? Should we retire some applications? Which should we leave as they are?
But another option is often overlooked: Replace the application with a SaaS alternative. Doing so means that we stop maintaining an on-premises system and switch to a SaaS app for the same functionality.
The most popular example is the move to Salesforce.com. Over the years, companies have switched from traditional CRM -- often a custom system -- to Salesforce's SaaS-delivered system. The objective is the same as moving to a public IaaS cloud, such as Amazon Web Services, Google Cloud, or Microsoft Azure: to reduce the cost of operating the application. However, SaaS is often easier to deal with.
I’ve found that most companies are too fast to push all applications to an IaaS cloud, and they often don't bother to assess the purpose of the application and its value to the company.
There are often better SaaS alternatives -- not only cheaper, but with better capabilities and better workflows -- for internal applications. And not Salesforce alone. There are SaaS-based HR systems such as the popular Workday, as well as accounting, manufacturing, learning, project management, and even office automation. By my count, there are more than 2,000 SaaS offerings, ranging from niche applications to integrated ERP and CRM systems.
Perhaps because SaaS is now 15 years old, IT has stopped thinking about it as cloud -- they confine the term's use to newer offerings like IaaS and PaaS. But SaaS is the original cloud, and it represents the largest part of the cloud market.
IT needs to put SaaS squarely back on its radar. There are many good SaaS apps that will do the job better for you than migrating what you have to an IaaS cloud. Just as you run a mix of commercial and internal applications in your data center, you should run a mix of SaaS and IaaS applications in your cloud.