In the end: On-prem
Because the lockdown in Germany is a good enough answer, we should perhaps take a closer look at the collateral damage. The economy and, of course, the SAP community are all about liquidity.
Put simply: If you run your entire SAP system in the cloud, you pay almost the same fees whether there is revenue or not.
In the Handelsblatt (see link) was to read "How the coronavirus pandemic is accelerating the trend towards cloud computing: Cloud services promise relief from contact restrictions and cost pressures. In the long term, however, a dangerous dependency could develop."
The authors Christof Kerkmann, Alexander Demling and Axel Postinett come to the right conclusion at the end:
"Because in times like these, it makes a difference whether you have to pay your rent, water and electricity as well as your IT infrastructure every day without any turnover or whether you can continue working on your old PC in the office with the old Word software until the fog lifts."
Many existing SAP customers have set up their own highly efficient data centers in recent years. Anyone running an SAP system on-prem now only pays for electricity and their IT staff, who are probably on short-time working.
After this pandemic and on the basis of the ongoing cloud fees, the CFO should carefully recalculate whether "on-prem" is not the wiser option in the end.