Apple have shown that you can get x86-tier performance, but it generally costs a similar amount of silicon and engineering effort as those x86 devices.
The lack of other competitors managing this suggest the arm ISA isn't "fundamentally" better at delivering that performance, it doesn't seem easier in engineering effort or silicon cost. The Apple products tend to outperform in perf/watt though, but that's hard to really compare as they're focusing on a slightly different market that favors that over "Peak Server Performance".
Is ARM better from a license POV? I also don't think so. Some people claim they want away from the "monopoly" of x86 copyright and license shenanigans from Intel and AMD, but I'd argue ARM control their ISA to a similar degree - you need to buy it off ARM to use it, and they have the right to revoke that license. See the Qualcomm/Nuvia legal mess, and that was when both companies were paying ARM already.
So in many ways I see ARM vs x86 as the "Coke v Pepsi" of ISAs, they seem pretty similar from the outside, serving pretty much the same use case (even if how they go around serving that use case is different), but some people online have rather dramatic opinions they confuse with "Proven Objective Fact".
RISC-V might be a good path away from just repeating the same "Single company controls all licensing" problem, but that's similar to how arm was 15 years ago - there's not really any proven high-performance cores approaching common "desktop" use cases yet, and at least ARM had to do a pretty clean re-write to go from then to now in armv8. Some of the things they "fixed" were very non-obvious until you actually tried to make a large, superscaler speculative implementation too - and who knows what pitfalls there may be in current ISA designs that trip over the "next" performance increasing techniques. Maybe they've managed to avoid all them for the near future, but like many things in R&D we don't really know until we get there.
The lack of other competitors managing this suggest the arm ISA isn't "fundamentally" better at delivering that performance, it doesn't seem easier in engineering effort or silicon cost. The Apple products tend to outperform in perf/watt though, but that's hard to really compare as they're focusing on a slightly different market that favors that over "Peak Server Performance".
Is ARM better from a license POV? I also don't think so. Some people claim they want away from the "monopoly" of x86 copyright and license shenanigans from Intel and AMD, but I'd argue ARM control their ISA to a similar degree - you need to buy it off ARM to use it, and they have the right to revoke that license. See the Qualcomm/Nuvia legal mess, and that was when both companies were paying ARM already.
So in many ways I see ARM vs x86 as the "Coke v Pepsi" of ISAs, they seem pretty similar from the outside, serving pretty much the same use case (even if how they go around serving that use case is different), but some people online have rather dramatic opinions they confuse with "Proven Objective Fact".
RISC-V might be a good path away from just repeating the same "Single company controls all licensing" problem, but that's similar to how arm was 15 years ago - there's not really any proven high-performance cores approaching common "desktop" use cases yet, and at least ARM had to do a pretty clean re-write to go from then to now in armv8. Some of the things they "fixed" were very non-obvious until you actually tried to make a large, superscaler speculative implementation too - and who knows what pitfalls there may be in current ISA designs that trip over the "next" performance increasing techniques. Maybe they've managed to avoid all them for the near future, but like many things in R&D we don't really know until we get there.