I worked for years on escape analysis in IBM's Java JIT compiler. We struggled to find any actual programs that showed any benefit at all. The real benefits of escape analysis were second-order effects like eliminating monitor operations on non-escaping objects, or breaking apart objects and putting their fields into registers (especially autoboxed primitives). The actual stack allocation wasn't really any faster than heap allocation, and a GC operation in the nursery doesn't even look at dead objects.
EA is basically a microbenchmark-killer. For real software, it's not often worth the trouble.