So for authoring an app, I tend to agree with you. Languages like Ruby/Python/Typescript are probably faster to get something working.
I try to consider productivity holistically though. With Go, there's a lot less fussing with the tooling. I've also found Go saves a lot of time when onboarding new teammates. This is because of Go's intentional decision to be conservative with syntax. After all, most developer time is spent reading, not writing.
I respectfully disagree with your preference to split your backend up over gRPC or HTTPS. I prefer the approach Shopify takes to break up it's monolith: https://shopify.engineering/deconstructing-monolith-designin...
Bud will support something like this in the future.