For 100M $ you can buy Proxmox, start advertising, scoop up all the lower end VMware customers and fill in the feature gaps according to customer demand over time.
The whole Oxide computer company raised less then $100 million $ as far as I know. With that money and open source they build not only service that can do live migration, but also the computer to run the whole thing on top.
Sure that's not a UI and doesn't include a lot of other stuff that VMWare does, but it does illustrate what a gigantic amount of money 100 million $ actually.
The underlying open source tools are so good, if you have the money to have real engineering team and combine them in interesting way and to costumize them for your needs, 100 million $ seems like it would go a very, very long way.
Specially when we are talking 100 M$ every year or something like that.
Live migration is a pretty hair-raising feature if you know how it is implemented internally, but nevertheless qemu/libvirt put in a vast effort to make it work and many Red Hat customers are using it routinely.