It depends on your timing. If you're extremely unlucky, you'll buy the new set of servers and the recession will hit right after you sign the PO. Probability says you're not likely gonna be that unlucky, so the recession will hit probably elsewhere in the physical servers' life cycle. A recession hits, and now there's a focus on cutting costs. With AWS, you don't have much choice - if you stop paying the bill, the servers evaporate into the cloud. Physical servers don't. You can change their replacement schedule and just wait arm few years more to replace them. Hopefully the recession has passed by then and you can buy a whole new pile of servers.

Really though, it seems like a hybrid on-prem/cloud approach is one to consider. Software like Anthos eases this, though there are also pitfalls with this approach too.