Eh. K8 is for orchestration, right, not performance.

Also adult site’s performance is insanely read heavy. They can cache the shit out of content and whatever is behind that doesn’t have to be the fastest. That model doesn’t apply to all software needs.

Sure, just about anything could work. With a dynamic language your hardware requirements will be about 10x more. But that's a tradeoff you might want for possibly faster development time.

When it comes to cost to performance ratio your best option is avoid cloud providers like the plague and go for good old bare-metal servers (from a third-party or on-premises if your scale warrants it). You'll get a 10x improvement without having to change any software at all. Then if that's still not enough you can consider switching languages.

What are you basing your 10x comparison on? What costs 10x less? Does it consistently cost as much?

I'm sure they would love to hear from you if you can cut 90% of their hardware costs without increasing other costs.

Based on these benchmarks - https://dizzy.zone/2018/01/23/Kestrel-vs-Gin-vs-Iris-on-EC2/ - Go could easily be reducing costs 10x at a PHP-based company. Just look at Go's memory requirements. It's insane.

Anecdotal reports basically, obviously 10x is just a round number I picked. I've seen a company that switched citing up to 40x hardware reduction going from Ruby on rails to Go.

10x cost savings is hardly unheard of.

I think you're significantly underestimating how well-performing PHP is, in the narrow but important field of serving dynamic web pages. Go (or Java, or C#) can be faster but you might be surprised that it's less of a slam-dunk win than one might expect. Python and Ruby basically aren't in the same league. Nodejs can be said to be licking at its heels, at best. Yes, seriously.

I'd put PHP somewhere under the middle of the list of languages/ecosystems I'd like to work in again (RoR, specifically, though not Ruby generally; non-TypeScript JavaScript; and gnarly AbstractFactoryImpl-style Java are all probably worse than it, IMO, and of course PHP deep in anything like Wordpress is pretty miserable) and I like Go quite a bit, but there's no denying that if performance is a top criterion PHP should probably be on your short list when choosing a language/ecosystem, and if PHP's not going to cut it then probably no scripting languages are on your list, and you're very likely looking real hard at C++.