I have spent a good chunk of my career at a Fortune 10 energy company.
We hired people who specialized in working with SAP, Oracle databases, MSSQL, messaging (think MSFT Lync), email infrastructure, physical servers for web apps, Cisco, desktop provisioning, application development, mobile device management, ticketing software, etc. etc.
It’s very hard and very expensive to acquire the right talent to manage a particular technology, administer it, support it, etc. Every vended software we work with has some company that looks at our name and comes up with some outrageous cost for a few licenses, dev seats, or whatever their business model is.
Acquiring the right quality talent is even harder. You bring them in. You try to teach them about your business so they feel valued and part of something big. They don’t stick around. They want to be at the Googles and Amazons of the world. They leave.
In this scenario, I’d rather use SQS than try to interview, hire, train, and make the hardware/software investment in running an SQS equivalent service in house. I don’t want to hire DBAs and build that profession in my org. It’s not our core business. My customers in the business don’t give a shit about it. They want something fast, reliable, and dependable.
Fundamentally, this argument of just do it yourself to save money is short sighted. There are a lot of factors. If you believe hiring Some internal teams is always cheaper than using managed services, you’re in for a world of hurt.