If you run things efficiently you're eaking every ounce of performance out of this hardware. A 30% performance hit means a 30% cost increase.
The bigger issue is for things that don't scale easily. That sql server that was at 90% capacity is suddenly unable to handle the load. Sure that could've happened organically, but now it happens (perhaps literally) overnight for everyone all at once.
Expect a bunch of outages in the next few weeks as companies scramble to fix this.
The important point about Go in this case is that it's fundamentally more efficient because it has real modules and can do incremental compilation.
Sometimes people don't realize this because they always use `go build` which, as the result of a design flaw, discards the incremental objects. When you use `go install` (or `go build -i`) each subsequent build is super fast.