A few years ago, yes. That's the point. But please, bring out the extreme cases first that don't make sense with it.
No, and its not an extreme case, it's a moving target. The iPhone today could run final cut of yesterday but if you want to do whatever the latest video editing is, (8k, spatial video, etc.) then you'll want more compute.
Thats the key misunderstanding of a request like this, if our computing needs stayed the same then yes, an iPhone today is more than capable of what we did 10 or even 5 years ago, but the fact is we demand more of our computers each day even with basic tasks. Just plugging in a monitor today is much more computationally intensive since its probably got a high refresh rate and a lot more pixels to push. Even the web today is far more demanding than it was in the past. Maybe it shouldn't be, but its not all bloat, more robust features, AI, etc, the "basic needs" are always changing.
You can see some convergence though and to your point it would be convenient for this to continue. Laptops today fulfill what most needed a desktop for in the past, and iPads are coming close behind since they have the same Mx chip as entry level macs now. And of course now we have games like RE4 running on iPhone. Which is awesome, but its still an issue of thermal dynamics. The iPhone can play RE4, but at a lower framerate and gets super hot and can't handle sustained load, so why not use a bigger device if you're at home? The same applies for all other computing tasks.
So certainly the baseline power is getting more consistent as recent silicon has gotten much more power efficient, but there will always be thermal tradeoffs with the size of the device, so its unlikely the iPhone (or whatever pocket device you prefer) will ever be that "do everything" device. (The iPad might get there.) And there's still the specialization of silicon to consider besides the raw power. In many ways, the gap between an Axx and a Mx is still sufficiently large, so while an A17 may appear faster than an M1 in benchmarks its not likely it would provide the same experience if you just load macOS on it.
Now, if I were to predict the future though, the "one device to rule them all" would be whatever the Apple Vision Pro looks like 5 years from now (notice it has an Mx chip, not a Axx chip). Or maybe neural link. However, even then you'll have other larger devices to wirelessly offload compute when you need to do something intensive (whatever "intensive" looks like in 2030).
