Maybe compared to Heroku or similar, but compared to a world where you're managing more than a couple of VMs I think Kubernetes becomes compelling quickly. Specifically, when people think about VMs they seem to forget all of the stuff that goes into getting VMs working which largely comes with cloud-provider managed Kubernetes (especially if you install a couple of handy operators like cert-manager and external-dns): instance profiles, AMIs, auto-scaling groups, key management, cert management, DNS records, init scripts, infra as code, ssh configuration, log exfiltration, monitoring, process management, etc. And then there's training new employees to understand your bespoke system versus hiring employees who know Kubernetes or training them with the ample training material. Similarly, when you have a problem with your bespoke system, how much work will it be to Google it versus a standard Kubernetes error?

Also, Kubernetes is really new and it is getting better at a rapid pace, so when you're making the "Kubernetes vs X" calculation, consider the trend: where will each technology be in a few years. Consider how little work you would have to do to get the benefits from Kubernetes vs building those improvements yourself on your bespoke system.