[bengale]

This seems a weird question. The Macbook being slower than your air doesn't mean that it won't be just as performant in 4 years, but no it won't be faster than a device that it isn't faster than now.

If the Macbook is fast enough for someone now, and their workload doesn't change, then yes, I'd expect it to be just fine for them in 4 years; just as the same can be said for the Air, or the others.

[Paulods]

Thats kind of my point. Its been almost 4 years and apple hasn't made the devices (at the same price bracket) any more performant.

Will the software they make over the next 4 years stay at the same level of requirements and run just as smoothly as everything seems to run on my air after 3 years?

I am not sure that is the case looking at how the OS is moving and how they are treating performance.