Interesting. Would your opinion change if you where only in charge of the API? I.e. VueJS/React/Angular on the top by another team..
It'll still be slower to develop and iterate initially with Go, than with a bodged PHP or nodejs backend.
I'm somewhat comparing apples to oranges, because you could of course create very high quality, well-designed PHP or nodejs code. In that case it'll probably not be any quicker. The point is that you can quickly bodge in PHP a lot of stuff which you couldn't in Go. In my oppinion this is a benefit of Go in the long-term, but a signifcant overhead in the short term when you just need to get things done.
To answer your question properly: I think programming language should be a financial choice for any company, and one of the highest cost factors is developer hours. All that i've described earlier is about optimising for developer hours.
If there's a nieche reason to prefer a language that may override all points i've described. For example, hardware support, availability of project-specific library, language preferences of customers, compliance requirements.
As for long term, i'd say 3-5 years is a tipping point, where maintaining PHP/Python becames more painful then just using Go. Probably a bit sooner for nodejs with the npm dependency hell. But i'd warn you about choosing Go due to planning your product to exist for more than 3-5 years. You'll almost certainly have multiple rewrites of your code before you get to a state where it actually lives for 5 years - if at all. Do yourself a favor and prototype in a quick language. Maybe even have your first versions out ugly and bodged. You'll have a chance to rewrite if and when you have customers and a working business model.
Lastly but most importantly, these are commercial considerations. For a non-commercial project, you should ignore these and optimize for developer-happiness instead. I like Go. I'd choose Go over PHP/Python/nodejs anytime as a developer. You should choose whatever you like the best. If you ask me, you should like Go the best :-)