Intel has a 5 year plan started last year to take back the number one spot in performance, efficiency, and fab capabilities. Its ambitious, but certainly not impossible. Apple is currently top in efficiency with M1 and TSMC's 5nm manufacturing, but Apple has lost talent and Intel is fabbing with TSMC now too (TSMC is building Intel an entire 3nm plant).
Apple aside, laptop and desktop sales are still x86's to lose, so unless both Intel and AMD take major stumbles, I dont see ARM shipping in much more volume in PCs than it does now.
I wonder if we will see Intel expand big time into more embedded industries (like they already are with vehicles) and then use that additional cash to buy out ARM and make integrated dies with both types of cores. A desktop or laptop CPU with both x86 and ARM cores for different uses (and maybe even high performance virtualization embedded at the hardware level) could be interesting - especially as more operating systems gain good support for both architectures.
Apple aside, laptop and desktop sales are still x86's to lose, so unless both Intel and AMD take major stumbles, I dont see ARM shipping in much more volume in PCs than it does now.