Idk about x86 itself minus legacy as it's defined by legal. However, Intel tried to clean-slate it at least four times. The first, i432, was revolutionary, forward-thinking, and overdid the hell out of the hardware side. Hundreds of man-years lost due to low, raw performance. Market only cared about the latter so rejected it.
Second was for BiiN parallel and high-availability system. Its i960 was a brilliant combo of RISC, HA, and security aspects of i432. Rejected by market due to no backward compatibility although used in F-35, some storage controllers, and so on. Still available for embedded but not the good version in the links. :( Especially see the manual and part with object mechanisms for containment/addressing. Cost them and Siemens a billion dollars.
Third time, in parallel with i960, was i860 RISC core for high-performance supercomputing and embedded systems. Had performance issues and just wasn't popular in general. Another loss.
Itanium combined RISC, VLIW, PA-RISC style security, and reliability features. EPIC/VLIW probably what did it in the most unfortunately because reliability, speed, and security combo were good. Link below is security features as they alone justified in imho over x86 and you probably never saw them in comparisons. Just dollars, GHz, and GFLOPS as if that's all that matters. Used in appliances, supercomputers, and workstations but going away probably at a cost of hundreds of millions of dollars.
So, Intel has tried to give us something better than x86 four times already at a cost of billions of dollars. To their credit, they tried and produced a few great designs with some flaws for sure but great in key ways. Market rejected them in favor of raw price/performance and backward compatibility with shit software. So, we're stuck with that given Itanium will go into legacy mode, VIA is loosing money on their x86 business, Transmeta was bought, and Loongons w/ x86 emulation are shaky investment.
Gabriel's Worse is Better is in full effect here...
