For everyone else, the effect is proportional. Someone with 1000x more stake is paying 1000x more.

Of course I mean everybody else. :)
But there are also 1000 x more small accounts than big ones, which all also pay the inflation - which is altogether quite a lot. Of course we can also call them 'stakeholders', too, but I guess you had big stakeholders in mind when you wrote that stakeholders pay the inflation.

And of course you have a higher risk the higher your stake is, but also a higher chance to make profit, if the STEEM price rises (that's why you originally invested money, I guess).

There is a huge difference.

Yes, that's why I put 'pay' in quotation marks. Content creator don't literally pay, but also contribute to the SPS by passing on a part of their possible rewards.
As (at least in in my opinion) 'content' is the unique feature of STEEM compared to other crypto currencies/blockchains and thus may become an important factor of a future increasing value of STEEM, I value time and effort, content creators invest in the platform as much as the money stakeholders invest.
Actually, I am getting maybe somwhat off topic here, but sometimes my impression is that (big) stakeholders tend to underestimate the value of 'normal little' users for the platform and the success of the blockchain.

Sure, but I'm absolutely going to vote in a manner that I believe spends (or does not immediately spend) those inflationary rewards in the manner that gets stakeholders the best value for the cost.

In your case I am absolutely convinced of that!
And even if my text above may lead to a different impression, I am very thankful that people like you invested lots of money!
However, did you read for example the comments of z8teyb289qav9z (we all know who he is) in this post: "You fucking suck."? No constructive criticism, no thoughtful weighting of words, just flags and insults. Unfortunately, not all big stakeholders act as responsible with their power as you do.