If you are running vpshere and move to proxmox, you are in for major differences.
Billions of have been wasted trying to get rid of the vTax. It has been rarely successful.
The open source will be eventually "good enough" like Postgres is "good enough" over Oracle, but this doesn't stop Oracle from taking in $50 billion every year.
A tech company can justify 30-50% R&D spend, which is where IT/Software falls.
As a non-tech company like ExxonMobil or UnitedHealth this is a much harder ask while being a distraction from other work your IT/SWE team needs to get done.
Time spend managing your custom OSS virtualization stack is time taken away from managing compliance, security posture, networking, data management, etc.
Why re-invent the wheel when it's cheaper to buy?
Don't forget Oracle: https://www.oracle.com/virtualization/
I agree
> effectively unlimited hc and budget
I disagree.
A company like Google or FB can build in-house tooling simply because they have entire dedicated teams of engineers to manage their environments in house to meet niche needs. A F10 like ExxonMobil or UnitedHealth cannot justify a FB size engineering footprint when their margins are much lower.
> find a competitive alternative platform to ESX
Yep. The issue is ESX is actually pretty good at getting the job done. Your alternatives from a supportability standpoint are HyperV from Microsoft (which will probably eat up the smaller ESX customers), Citrix Hypervisor (owned and operated by ex-Broadcom leadership), and IBM RedHat's KVM (which requires you to work with IBM for Professional Services).
At the end of the day, you as a CTO or Platform team don't want to be fully OSS. Not because OSS is crap software (anything but), but because a pure OSS play doesn't provide you a dedicated support engineering team if shit hits the fan nor SLAs and monetary compensation if shit breaks.
This is why most OSS core companies max out revenue via a Professional Services play. RedHat is a notable example of this.