This does not make sense. Firefox would be taking minutes to open a page that Chrome opens within a second or two. And if Chrome was doing aggressive pre-fetching, then it should be using more memory, no? And yet the opposite is the case.

Not denying your experience but if it is taking "minutes" then that sounds like a highly specific glitch that you should try to debug.

Speaking personally I have used Firefox pretty much exclusively for 20+ years, always on low-end hardware. It's been years since I last had any performance issues.