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.
I'm sure they would love to hear from you if you can cut 90% of their hardware costs without increasing other costs.
10x cost savings is hardly unheard of.
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++.