Alright, since this seems to be a pretty active discussion point in this forum right now, let’s go over the x86 vs. ARM a little bit. I will try and break this down for people of all knowledge levels.
These two architectures represent fundamental differences in how the CPU interprets instruction sets. ARM uses RISC (reduced instruction set computing), and x86 uses CISC (complex instruction set computing). So they are fundamentally different down to the assembly language representing all the higher order code being developed.
Think of this like x86 as Japanese, and ARM as English.
There is near no direct 1:1 correlation. You can get close, and you can translate between them, but they are very different.
In order to go from ARM to x86, you either need a different program entirely, or you would need a way to fundamentally recompile it for x86 architecture. This is a nightmare. And this is just in general; I haven’t even dug into Apple’s specific mess yet.
Keep in mind too, if you have any performance optimizations, any at all, good luck not breaking things. ARM has instructions that just don’t translate to x86 and vice versa.
Now, this is all well and good, but we are talking about Apple’s specific ecosystem in this context. Does this change much of the difficulty and complexity?
Nope. If anything, Apple just makes developing for x86 chips more pointless, not less.
There is never going to be another intel chip on Apple hardware again unless something changes again in another decade.
Why would a developer build for an architecture that is already deprecated? This makes very little sense. Most apps in Apple’s ecosystem now are built exclusively for apple silicon, and that’s where all of Apple’s new customers are going to be over time. Hell, I wouldn’t be surprised if Apple enforces that behavior themselves. This is very much their MO. Gatekeep, and if your old Mac stuff is outdated, by a new Apple thing. Do I agree with this? No. Does Apple care? Also no.
For those who ask “Windows is x86! They’re surely building a Windows app, why can’t they just support intel Mac stuff then?”
Weeeeell, you forget that we’ve only been discussing the lowest levels of compute. We haven’t even touched on differences in OSes. Remember, Macs are still Unix-like systems at their core. Windows is MS-DOS. Again, this adds its own complexity when trying to implement cross compatibility. Just because two computers use the same CPU architecture, does not imply any degree of ease of cross-compatibility. See iOS vs. Android. Of course, there are ways to make this easier and more painless, but it still take certain degrees of time, and the more compatibility you add, the more complexity you add, because the unique quirks between hardwares, OSes, and architectures stack up fast. It can overwhelm you quickly.
So, to end this, the reality of why it’s likely in Apple Silicon first is because the people at OAI probably built it on their laptops using something like Swift (did I forget Apple even has a preference for what programming language you use to build on their ecosystem?), and it takes 1000x less braincells and effort to just make something work well for one architecture on one OS, and branch out from there. It’s quick, easy, simple, long-lasting, and will translate easily to iOS.