The counterarguments are, basically:
1. vgo focuses on the wrong issue (if you're spending a ton of time resolving and re-resolving your dependency graph, maybe the issue is your build process).
2. vgo will get the wrong answers and/or make development much harder
There's a long writeup of some of the ways vgo can go wrong here: https://sdboyer.io/vgo/failure-modes/ and some background here: https://sdboyer.io/vgo/intro/ among other places. And there was a lot of discussion here: https://news.ycombinator.com/item?id=17183101
I'd say there's about a 3% chance vgo ends up being a smashing success that revolutionises package management and gets copied by everyone else, a 30% chance that vgo works well for golang due to their unique requirements but has nothing to offer anyone else, and about a 67% chance it ends up being a failure and being scrapped or heavily revised to scrap the novel, controversial and (arguably) fundamentally broken ideas that set it apart from every other package manager.
But fundamentally, the reason the cargo people aren't copying it right now is that it doesn't even really claim to have advantages over cargo for rust. (There are some quirks in the golang ecosystem which mean you end up analyzing your dependency tree way, way, more than you do in basically any other common language. That makes speed important for golang, but for everyone else, it's almost meaningless.) "We make the unimportant stuff fast at the expense of getting the importing stuff wrong" isn't very compelling. :)
Of course, the vgo people would phrase it as "we make the important stuff fast and we get the important stuff right", so...time will tell. But don't expect anyone to copy this quickly; it remains to be seen if it'll even work for golang, and it'd need to be a huge step up from the current state of the art to make it worth switching for other languages and ecosystems.