It does seem like we should stop counting how many transistors fit in how much space. At this point, size isn't the limiting factor. Tracking either the cost of a unit of processing power or the total processing power of the planet would be more meaningful in benchmarking technological progress.
The main point of the decline of Moore's law is that it is about economics as much as it is about the size of the features on a chip. Even if someone does figure out how to get to 5nm it may not be cost effective to mass produce chips at that size. Already we see that Intel can't afford to keep up with shrinking scale as they've moved away from their tick-tock cadence to tick-tock-tock. Intel has the most advanced materials research in the world and they can't make it work cost effectively. That indicates pretty clearly that the exponential scaling of transistors is over. Smaller transistors may still be possible or new materials may emerge but the future scaling isn't going to happen on Dr. Moore's timetable which is the basis for Moore's law.
On top of that, it is not quite clear what would the hardware designers achieve with an increased transistor budget. CPU cores are becoming increasingly small in comparison to the surrounding circuitry (graphics, caches, control logic). We are bumped on clock speeds, too.
Well that would seem to call for adding specialized coprocessors or even FPGA's, not just more CPU cores.
If you're going complete coprocessor, you can do much more like Apple has done with their motion coprocessors or the secure enclave.
The lack of progress on thread perf is a huge problem.
E3 xeons (which are essentially i7s with ECC) score higher; But if you care about single thread perf then you get an i7-4790k which has been top of the list since 2014. Zero progress has been made since then.
[0] https://web.archive.org/web/20130810001315/http://www.semico...
That, combined with Amdahl's law, means that the unmistakable levelling off that we're seeing now will place some pretty firm limits on what we can compute until we move off of silicon.
Imagine that we have the technology in place to manufacture silicon chips at 2nm. How would we design CPU cores with a substantially better single-thread performance, when clock speed is limited? Optimization techniques like OoO execution and register renaming have already been pushed to their extremes. Increasing caches beyond a certain point has been shown to deliver diminishing returns.
We just don't know fundamentally how to design a substantially faster CPU core.
PS: It's a Gatling CPU...
So yeah, the party's definitely over and it's down to more efficient software at this point until we get optical computing or rod logic or something crazy like that.
Not to mention there is lots of room for improvement on the memory front, stalls kill performance.
Going by a more general version of Moore's Law (cost of equivalent processing power being halved about every 18 months) then I don't see any end in sight, though we might need to change paradigms on what processing power means every now and then.
28nm: The Last Node of Moore's Law http://www.eetimes.com/author.asp?doc_id=1321536