>Individuals don't care about their ability to change their percentile, they care about their ability to change their total income. I think most individuals would prefer a "non-mobile" $60k increase in income versus a "mobile" $40k increase in income. You can't spend percentiles.

I highly dispute this. Take it as a completely different world view but I think if people were given a choice:

1 >a nominal income of $100k for you and a nominal income of $200k for all your neighbours

2 >a nominal income of $75k for you and a nominal income of $60k for all your neighbours

A lot of people would opt for choice 2. I myself am not sure whether I'd go for 1 or 2.