People keep bringing this up when talking about Intel's botched mobile strategy, but IMO it just doesn't apply. Itanium was marketed based on features for servers that frankly weren't really popular. People always wanted one of the following things:

* performance per dollar

* performance per watt

* highest single threaded performance

* lowest possible power draw

Itanium AFAIK improved neither of these, or it did so only for very narrow usecases. What Intel needed was either (a) an ARM competitor and/or (b) a processor with large vectors and a SIMT-like parallelisation model (i.e. a Tesla competitor). In both of these cases they didn't think twice before just throwing x86 at the problem until the pain goes away... which it never did.

Just because the Itanium was a failure doesn't change the fact that Intel have tried several times to get away from x86. So it's unfair to claim that Intel have relied purely on x86 in order to shut out competition. Of course, they're not going to quit x86 until another instruction set has been proven more popular to the market and they have made attempts to create that instruction set.

Agreed, some people just don't realize how many arches were tried at Intel, i432, i860, i960 etc...

Still missing the point. Which non-x86 architectures targeted at low power or HPC - if you count computer graphics as a subset the main growth markets - were tried in the last 15 years?

Why trying to win people over on compatibility if they have to rewrite their software anyways for other reasons, especially after ARM took the largest market share in mobile?

I think you look at it the other way round -- it is not so much Intel who wanted to win customers over compatibility, but rather the customers who had to port their software, and suddenly saw a possibility to not do that.

It took a while to Intel to accept that the mobile-app providers won't invest the same effort in porting their apps from ARM to x86 given the market penetration, but I don't believe it was a suprising outcome to them.