One reason is that Apple sold subsidized devkits to developers starting around 6 months before Apple Silicon launched, while the X Elite devkit was not subsidized, came with Windows 11 Home (meaning that you had to pay another $100 to upgrade to Pro if you were an actual professional developer who needed to join the computer to your work domain), and didn't ship until after months after X Elite laptops started shipping. As a result, when the X Elite launched basically everything had to run under emulation.
I think another reason is Apple's control over the platform vs Microsoft's. Apple has the ability to say "we're not going to make any more x86 computers, you're gonna have to port your software to ARM", while Microsoft doesn't have that ability. This means that Snapdragon has to compete against Intel/AMD on its own merits. A couple months after X Elite launched, Intel started shipping laptops with the Lunar Lake architecture. This low-power x86 architecture managed to beat X Elite on battery life and thermals without having to deal with x86 emulation or poor driver support. Of course it didn't solve Intel's problems (especially since it's fabricated at TSMC rather than by Intel), but it demonstrated that you could get comparable battery life without having to switch architectures, which took a lot of wind out of X Elite's sails.
I think another reason is Apple's control over the platform vs Microsoft's. Apple has the ability to say "we're not going to make any more x86 computers, you're gonna have to port your software to ARM", while Microsoft doesn't have that ability. This means that Snapdragon has to compete against Intel/AMD on its own merits. A couple months after X Elite launched, Intel started shipping laptops with the Lunar Lake architecture. This low-power x86 architecture managed to beat X Elite on battery life and thermals without having to deal with x86 emulation or poor driver support. Of course it didn't solve Intel's problems (especially since it's fabricated at TSMC rather than by Intel), but it demonstrated that you could get comparable battery life without having to switch architectures, which took a lot of wind out of X Elite's sails.