>When an individual faces the choice on how much to depend on salary and how much on investment income, I don't see how productivity of labor has any relevance.

I was saying this in reference to how much we get paid. As a reflection of value / worth. Compared to the value generated, our salaries are relatively small, and its hard to argue otherwise when you look at productivity gains.

If you want to capture more of those gains, being invested in index funds is a good step in that direction.

>Also, we are mostly software developers here, and dev salaries certainly have kept up with inflation.

Even if this is true - and I don't know that it is so broadly true that it can be accepted as the median circumstance of HN users - that situation won't last forever, and more importantly salary is not controlled by you its controlled by another entity.

The entire premise of the conversation is convert your salary - something you may depend on but isn't something you have sole control over - into things that you do have more control over (index funds) or effectively sole control over (real estate investments most commonly).

This allows you to decouple your wealth from any single entity, which is the central goal.