Think back then it was all about massive databases - that was where the big money was and x86 wasn't really setup for the top end load patterns of databases (or OLAP data lakes).
They even had a chance with mobile chips using ATOM but ARM was too compelling and I think Apple was sick of the Intel dependency so when there was an opportunity in the mobile space to not be so deeply tied to Intel they took it.
The problem with mobile was that it fundamentally required low-margin products, and Intel never (or way too late) realized that was a kind of business they should want to be in.
Was it though ? They made a new CPU from scratch, promissing to replace Alpha, PA-RISC and MIPS, but the first release was a flop.
The only "win" of Itanium that I see, is that it eliminated some competitors in low and medium end server market: MIPS and PA-RISC, with SPARC being on life support.
HP-designed later cores were much faster and omitted x86 hardware support replacing it with software emulation if needed, but ultimately IA-64 rarely ever ran with good performance as far as I know.
Pretty sure it was Itanium that finally turned "Sufficiently Smart Compiler" into curse phrase as it is understood today, and definitely popularized it.