But what have we learned in these past 20 years?
* Computers will continue to become more parallel -- AMD Zen2 has 10 execution pipelines, supporting 4-way decode and 6-uop / clock tick dispatch per core, with somewhere close to 200 registers for renaming / reordering instructions. Future processors will be bigger and more parallel, Ice Lake is rumored to have over 300-renaming registers.
* We need assembly code that scales to all different processors of different sizes. Traditional assembly code is surprisingly good (!!!) at scaling, thanks to "dependency cutting" with instructions like "xor eax, eax".
* Compilers can understand dependency chains, "cut them up" and allow code to scale. The same code optimized for Intel Sandy Bridge (2011-era chips) will continue to be well-optimized for Intel Icelake (2021 era) ten years later, thanks to these dependency-cutting compilers.
I think a future VLIW chip can be made that takes advantage of these facts. But it wouldn't look like Itanium.
----------
EDIT: I feel like "xor eax, eax" and other such instructions for "dependency cutting" are wasting bits. There might be a better way for encoding the dependency graph rather than entire instructions.
Itanium's VLIW "packages" is too static.
I've discussed NVidia's Volta elsewhere, which has 6-bit dependency bitmasks on every instruction. That's the kind of "dependency graph" information that a compiler can provide very easily, and probably save a ton on power / decoding.