that plot of "the sweet spot of getting to the ikea effect" is a mediocre visualazation... it implicitly puts "contribution" and "value" on the same axis with no way to decouple them.
my biggest question that isn't answered is "how do you define contribution?". It's not a lot of work (because that's effort), and it's not how much it's worth in the end (because that's value). So... what quantity are we talking about, exactly.
I found the plot a bit odd also. But I don't consult designers for mathematical problems. The text communicated to me that contribution and value are not directly proportional.
The "quantity" of contribution is measured on an emotional scale. It's how the individual feels about the impact of their effort. This is different than the value of their effort. For example, someone telling a joke, the value stays the same, x% laugh at it. But if the joke were to go viral and tens of thousands of people laugh, the contribution is increased (making more people laugh). But the value is the same. The audience had x% chance of laughing.
A different example is the original Star Trek. The value of showing fictional technologies like videoconferencing and cell phones was very low. It was part entertainment value and mostly expedited storytelling. But the contribution to human society is hugely significant, just by prompting people to action, to pursue the development of such tech, and also by helping people visualize how such tech would simplify things and make time spent more productive.
my biggest question that isn't answered is "how do you define contribution?". It's not a lot of work (because that's effort), and it's not how much it's worth in the end (because that's value). So... what quantity are we talking about, exactly.
edit: remove extra words