There's some truth to the fact that Itanium had terrible execution, but a number of attempts afterwards have been made as well, high end general purpose VLIW is just not the way to go.
Note the high end and general purpose, if you're talking about smartphone cores or supercomputing, then VLIW can actually perform quite well, and indeed Itanium enjoyed decent success in supercomputing and the Qualcomm Hexagon, albeit not really general purpose, finds itself in many processors doing solid work.
Yup, that's the other classic mistake, committing to a design based on theoretical rather than practical merits.
It's a tempting way to do things, it's very difficult and expensive to spin up and maintain dual development and production pipelines in parallel. But more often than not that's often the best way to go about things. Sometimes you make missteps that seemed sensible at the time. Sometimes you torpedo your whole business because you take too far a step back and you can't even survive long enough to let the new thing mature. Look at Intel, they've had multiple missteps that did tremendous damage to their business. They jumped on the netburst architecture bandwagon and that turned out to be a dead end. The Core architecture basically grew out of their Pentium Mobile work.
Note the high end and general purpose, if you're talking about smartphone cores or supercomputing, then VLIW can actually perform quite well, and indeed Itanium enjoyed decent success in supercomputing and the Qualcomm Hexagon, albeit not really general purpose, finds itself in many processors doing solid work.