Honestly, I'd assume both income and wealth are part of an abstract concept I'd call, in this instance, 'capital'. The specific ways both are taxed or regul

Honestly, I'd assume both income and wealth are part of an abstract concept I'd call, in this instance, 'capital'. The specific ways both are taxed or regulated depend too much on individual circumstances and governments, but the main point is you can't use a simple model that shows a 'well-off' income earner can make it into the top n% in 27 years, if the assumptions required to get that to work also gives the n% a greater or equivalent benefit.