CISC is dead, it's mostly irrelevant, all modern computers are RISC based. x86 CPUs merely have a micro-op translation system. That imposes some overhead, but in modern CPUs with gigatransistors that overhead isn't that great, and usually not a bottleneck.
The lesson of the last 20-30 years is that the ISA is almost entirely tangential to performance. There are some cases where that's not entirely true (like VLIW), but for the most part it still holds. What matters is the core design at a hardware level. And there it would be the height of foolishness to bet against Intel. They've been challenged multiple times by multiple world-class competitors, and they've demolished them.
Why is it so hard to imagine a world where multiple competitors have their niches? Look at iphone vs android, who are in the exact same market, for example, there's room for diversity and competition. The only way Intel could "die" is if they stop paying attention and stop caring about competing, and I just don't see that happen. At the end of the day they still have a ton of talent, the best fab capability and capacity in the world, and the ability to execute on projects successfully.