I agree but it there is another facet to this as well.

In your example if you wanted to buy something and realize you cannot afford it then working towards it now is, in part, living in the now.

It is working for the future but based on emotions that are happening now, for you may not know if you even want it in the future.

I suppose, in that way you could view it either way.

And yes, it is also true that past experiences teach us, but they also limit us. Fire may be hot, but what about things such as rejection, where do you draw the line there?

You may assume that you will get rejected again but maybe that is false inference. In this case the past only limits your actions based on patterns that work in general but never in a specific case.

In which case there is a merit to holding your hand in the fire again (metaphorically speaking) for it may not burn you that time.

Of course, literally speaking that is a dumb idea, the question is where do you draw the line between where the past helps and where it hinders?

I am not saying you must live in the moment 24/7, and you are right that it is drastically oversimplified (I would have to write a whole book to get even close to explaining it all... probably multiple), but it is about not always accepting that the future or the past are helpful and being aware of when to let either go that helps life the most ultimately.

Neither the past, the present or the future are always helpful. But we put too much trust in our thoughts of the past and future and abandon the now more often than not.