No. If you agree with the "percent of income/gains" framework we have no fundamental quarrel, but I want to point out that the way you phrased your point was indistinguishable from partisan economic-right opposition to this idea, which aims to bait people into betraying their class interest by understating their labor interest and overstating their capital interest. "You own some stocks in your 401k so you are capital class" is the usual argument, but the overwhelming majority of non-retired people with a 401k get more income from working than from the appreciation in their 401k and should vote accordingly.