The $100 boundary is far too low and it’s nothing to do with being pretentious; it needs to be at least an order of magnitude higher to prevent the torrent of absolute ***** pouring through the gates. At $100, a shovel-ware developer need only sell a small number of titles with a price of less than $3, and they can make considerable revenue from additionals like trading cards. If the only barrier to entry for Steam is financial, then it needs to be a hurdle sufficient enough to ensure quality. There are plenty of these low price asset flip games that serve no purpose other than to give people achievements and generate trading cards that have made around 1000 sales per piece - this suggests that the barrier to entry needs to be at least $2000 per title.
The “poor developers who can’t afford more than $100” is a trite one, and it’s also a fallacy. If someone has confidence that their product is worth selling, then the means to acquire the access fee is within their reach (investment, small business loans, publishers, crowdfunding, and more). If they don’t believe they can make their return on the entry fee, or they can’t find anyone to help them raise it then I would hazard to suggest that the game is not actually worth selling.