I worked for a company that was on a receiving end of a similar GPL legal action (though not busybox-based and not from SF Conservancy). I'll tell you what will happen next. VMWare will (a) write a drop-in in-house replacement for busybox (b) they will show that busybox is not an principal part for ESXi and that it can be easily swapped for the in-house replacement. At this point they will release the busybox sources, potentially including the in-house version, but not under GPL. This will hinder the lawsuit, but it will keep dragging on until everyone gets tired of its pointlessness and then it will get quietly dismissed to the mutual satisfaction of both involved parties.
The thing is that it's not that VMWare is evil or unethical. It's just that this GPL thing doesn't even register on their legal radar, so it never percolates down to engineering. Similarly any concerns raised by engineering are never taken seriously by the legal council. It's really as simple as that.