VMWare is more than virtualization.
OpenStack technical trainer here:
If you think of VMWare in 2026 as virtualization only solution, like we still are in 2006, then sure, KVM, or QUEMU, Xen, BSD's VMM, or Hyper-V are cromulent options.
But nowadays, VMWare, XenServer/Xencloud, on Premises Azure et al are used to make Private Clouds, or the fleets running on them use a few advanced functions beyond virtualization, with all that implies. Very few workloads are "virtualization only", not touching any of the advanced or the cloud-dy functions .
The linux equivalent would be OpenStack, with all the load that implies.
And yes, many of the FOSS solutions run KVM under the hood, with a few exceptions like Xen based ones, or BSD's vmm and vmmd, but again, what really counts in 2026 is not the Hypervisor, but all the other advanced stuff built atop of it.
There is another aspect in this too, and it is Application support. Many ISVs certify their platforms/apps on specific OSs/Distros running on Specific Hypervisors.
So, for instance, your ISV may say: Only Windows Server 2022 or 2025 only, RHEL 10, or Suse 16, on top of VMWare, Openstack or Azure.
And there you are, for those workloads, you can forget about all the other solutions (obscure or not) that homelabbers love to peddle. Big corpos can pressure smaller ISVs to support their preferred solution, but the big ISVs will most likely put a few options on offer, and that's it.
In those cases, large intitutions (like T-Mobile, the focus of the article) have 100s or even 1000s of ISVs some more crititcal than others, and they need to reach commonality of solutions, or personel requirements ballon (the legacy VMWare group, the Openstack group, the XenCloud group, the ProxMox group, the Azure group, the Nutanix group, the....) along with all the other support functions (negotiations and keeping track of support contracts for each technology). A veritable nightmare. So, unlike homelabbers, Big corpos will probably go to a one or two vendor solution for their internal clouds.
Since VMWare was the leader, and for many lustres a model citizen, pretty muche every single ISV offered them as a supported option, therfore, it was the easier default.
So, get out of VMWare ASAP, but be warned it will be hard, as you need to provide alternatives to the advanced functions, and align certification requirements for support.
Also, use this as a clean-up opportunity . Retire redundant APPs, retire inhouse stuff with big technical debt, move it to either functions inside SW you already own (even if they are not completely taylor made) or to SaaS. That way your VM stable will be smaller, migration will be faster and easier, and the bill from whatever replaces VMWare will be "even moar" cheaper.