The main limiting factor for embedded is cost. If you start from the position that you want to run something that was written in Java then there will be a selection of ways to do that. Most Java applications will require external RAM to the CPU, the lowest cost DRAM chips will be whatever is used at that time in high-volume consumer electronics, when ARM chips with Jazelle were introduced the DRAM capacity that represented this optimal price had increased by a lot from when those ARM chips were designed, increased to the point that the increased memory requirements of a JIT were no longer a problem.