How do you arrive at "wind up fairly comparable"? If you merely contributed $40 in the last Presidential election, your money counted twice as much as your vote, relatively speaking.
If you're looking at actual donations versus possible donations, the point is what you could do with your money, not what the average person actually does.
The original statement about rounding errors, which you compared votes to, was:
'Dollars, on the other hand - Bill G has quite a few orders of magnitude more than you. So many infact, that your "dollar votes" end up being a rounding error either way - with him or against him.'
Dollars Bill Gates has (or rather, net worth) divided by the net worth of the median individual is not terribly far from the voting population over one.
This is not a terribly meaningful comparison, I just thought it interesting that they wound up in the same ballpark.
The important point was that your vote matters a ton more on local things than things further away, though your dollar can go further there as well to be sure.
Got it. That is an interesting comparison (but as you say, not necessarily very meaningful).
It would be interesting to compare the political donations of wealthy people like Gates with those from regular folk. Does it scale with net worth? Do rich people give more or less, relative to what they have, to political causes?
You're right that your vote matters more locally, but so does your money, so I think the potential difference in influence remains similar.
I'd weakly expect the wealthy to donate less, on average, relative to their disposable income. Whether that winds up more or less relative to their income depends on a host of factors... There's also liquidity to factor in... and of course Bill Gates can probably manage a fair amount of influence before donating anything (I'm not sure whether that's gone up or down since he moved from MS to charity).
"You're right that your vote matters more locally, but so does your money, so I think the potential difference in influence remains similar."
There's another interesting factor at play, which is that there can be unintended effects from wealthy people spending lots of money on politics, because you can't just directly buy votes.
For example, if Bill Gates decided to put $5 billion behind electing his candidate of choice in the next Presidential election, it would probably backfire spectacularly. Just looking at the numbers, he ought to be able to determine the election on his lonesome, since money talks and he'll outspend the other guy by a hefty margin. But the idea that a rich guy is effectively trying to buy the election would mobilize people to fight against it on a huge scale. You can see this at work in a smaller scale with the infamous Koch brothers, and the smaller scale backlash their spending has generated from people who oppose their views.
So not only do you have to look at how much people can and do spend, but also how effective that spending is. The marginal utility of political spending probably has a weird curve, and almost certainly can become negative once you reach a certain level.
If you're looking at actual donations versus possible donations, the point is what you could do with your money, not what the average person actually does.