I don't see a bright future for ruby, I think it had some lead advantage, but RoR/opinionated-design really cut down the options for innovation with a Ruby based web dev group. It is interesting to see how diametrically opposed philosophy of Ruby the language is from the RoR community, it is like Ruby created a liberal blank space and RoR immediately filled it with conservative inflexibility.
Php is in an interesting position, but I think ecommerce systems catching up and offering more integrations will erode its position. It is very expensive to hire and retain loyalty on a php project, especially when it is of any complexity since anyone who will tolerate it and understands CS has plenty of other options.
If I had to say what will trouble JS, it is C++ as the VM. Too many groups will lack members that are able to look bellow the scripting layer when the inevitable low level problems occur.
Personally, I see the future as a war (and up/down stack integration) between JS/v8 and LLVM based languages. While other options will keep their markets for years, they have no solid positions for growth. Python will hold on as long as it has the academic position, but it needs a better relation with LLVM or clever curriculum builders will choose another language to teach using only one easy enough language up through compilers, with llvm-ir replacing assembly in a way that makes sense given the Arm/Intel war could go either way now.