If you think of an SOC, the chip in your phone, more and more of the real estate is being dedicated to specialized compute (AI accelerators, GPUs, etc. vs general purpose compute (CPU).
At the enterprise scale, one of the big arguments NVIDIA has been making, beyond their value in the AI market, has been the value of moving massive, resource intense workloads from CPU to more specialized GPU acceleration. In return for the investment to move their workload, customers can get a massive increase in performance per watt/dollar.
There are some other factors at play in that example, and it may not always be true that the transistors/mm^2 is always lower, but I think it illustrates the overall point.
Basically, every single credit card sized security chip (including actual credit cards, of course) is a small processor running Java applets. Pretty much everyone has one or more in their wallet. I'd assume those were actual Java CPUs directly executing bytecode?
Not sure: https://en.wikipedia.org/wiki/Java_processor doesn't seem to mention any in current use. I am ignorant of the actual correct answer: I had simply presumed it is simpler to write the virtual machine using a commercial ISA than to develop a custom ISA.
Java Card bytecode run by the Java Card Virtual Machine is a functional subset of Java 2 bytecode run by a standard Java Virtual Machine but with a different encoding to optimize for size.
https://en.wikipedia.org/wiki/Java_Card_OpenPlatform has some history but nothing jumped out to answer your question.Patriot Scientific's Ignite processor family https://www.cpushack.com/2013/03/02/chuck-moore-part-2-from-...
ARM Jazelle technology https://developer.arm.com/documentation/ddi0222/b/introducti...
https://www.eetimes.com/nazomi-offers-plug-in-java-accelerat...
It's all dot-com era stuff and Sun Microsystems also created a Java OS that could run directly on hardware without a host operating system.
That's about it
Not to say that improvements and doing more with less are impossible, they probably aren't, but it's going to require significant per design human effort to do that.
There are the really obvious ones like on-board GPUs and AI accelerators, but even within the CPU you have optimizations that apply to specific kinds of workloads like specialized instructions for video encode/decode.
The main "issue", such as it is, is that this setup advantages vertically integrated players - the ones who can release software quickly to use these optimizations, or even going as far as to build specific new features on top of these optimizations.
For more open platforms you have a chicken-and-egg problem. Chip designers have little incentive to dedicate valuable and finite transistors to specialized computations if the software market in general hasn't shown an interest. Even after these optimizations/specialized hardware have been released, software makers often are slow in adopting them, resulting in consumers not seeing the benefit for a long time.
See for example the many years it took for Microsoft to even accelerate the rendering of Windows' core UI with the GPU.