A company would like to move all its on-premises platforms to the cloud. The company has enough skilled Linux and web-server engineers but only a couple of skilled database administrators. It also has

Running web servers in PaaS removes OS-level control that the skilled Linux and web engineers are qualified to manage and would use effectively in IaaS.

Running everything in SaaS wastes the company's substantial Linux, web-server, and database administrator expertise by offloading work those staff are fully capable of handling.

IaaS for web servers leverages the company's strong Linux and web-server engineering teams, who are capable of managing the full OS and application stack. PaaS for databases reduces infrastructure management overhead for the few available DBAs, letting them focus on database administration rather than server provisioning. SaaS for email eliminates the need for any in-house email infrastructure expertise, which the company lacks entirely.

Running everything in IaaS would require the small DBA team to also manage database infrastructure at a level beyond their capacity, and would demand email expertise the company does not have.