Capex may also require you to take out loans

Which is incredibly difficult in the public sector. Yes, there are various financing instruments available for capital purchases but they're always annoying, slow and complicated. It's much easier to spend 5k per month than 500k outright.

Your numbers don't line up, if you are spending 5k in cloud costs, and on prem is 1/3 of cloud. At 48 month replacement cycle, 1/3 of 5k * 48 months is 80k. So it is 80k vs 5k a month for 48 months.

I think the primary reason that people over fixate on the cloud is that they can't do math. So renting is a hedge.

You hit the nail on the head regarding the math. Most teams treat cloud costs as an inevitable tax rather than an engineering variable. As someone with an accounting background turned Cloud Architect, I see this 'math gap' daily. Usually, it's not a cloud vs. on-prem issue, but a lack of infrastructure discipline—idle resources and unoptimized NATs burn through that 48-month budget faster than hardware depreciation ever would. I’ve been using a 'Hardened by Design' framework to cut this waste by 50% without the overhead of moving back to a data center. Efficiency is often just better IaC.

It’s not really about the numbers though.

Even spending 10k recurring can be easier administratively that spending 10k on a one time purchase that depreciates over a 3 year cycle in some organisations because you don’t have to go into meetings to debate whether it’s actually a 2 or 4 year depreciation or discuss opportunity costs of locking up capital for 3 years etc.

Getting things done is mostly a matter of getting through bureaucracy. Projects fail because of getting stuck in approvals far more often than they fail because of going overbudget.

> It’s not really about the numbers though.

Of course not.