I'm in small Devops team and people are pissed off. Thankfully Proxmox works just as well for us (some would say better). Even a large-scale migration seems scriptable to me.
Proxmox looks great, but unfortunately it doesn’t come with encryption oob and manually applying it comes with feature loss and other problems. ZFS vs encryption is a bad place to live. You of course need encryption for your VMs on the Enterprise.
Proxmox is a lovely piece of software, highly recommend to everyone. But I think Proxmox and vSphere target rather different scales of cluster. Proxmox starts to choke once your past 20 nodes or so. Corosync just wasn't designed for huge clusters.
I think the price hikes have made the "medium" use-case more uncertain.