That’s certainly not the assumption here. The appeal is, as I said, that the systems would be more predictable and tractable, instead of being a tarpit of complexity. It would be easier to reason about them, and about their runtime characteristics. Side-channel attacks wouldn’t be a thing, or at least not as much. Nowadays it’s rather difficult to reason about the runtime characteristics of code on modern CPUs, about what exactly will be going on behind the scenes. More often than not, you have to resort to testing how specific scenarios will behave, rather than being able to predict the general case.

I guess I don't know that I understand why you would dream of this, though? Just go out and program on some simpler systems? Retro computing makes the rounds a lot and is perfectly doable.