For starters, this doesn't even seem to fix the problem stated, "The top developers are 25 times more effective than the average developer, but their salaries don’t reflect that". So you give a guy $3K pop if he would earn a salary of 100K... great, but that doesn't even address the differences in salary unless he continually changes jobs. I am also not convinced this service raises the average amount developers would make.
From the employers perspective, it's ridiculous to determine how much you'd pay someone without interviewing them first. People develop the longer they spend time at a company, and if you expect them to be worth your original offer in a few years, you are now forced to hire them for your original amount (by over paying for their current skill set) or just decline them an offer. Now if I'm not mistaken, that's encouraging employers to overpay for less productive talent... which is in direct contrast with the goal specified above.
This seems more inline with just increasing the overall salary for developers, and that's laudable, but you cannot build a developer job board claiming to just sell the best talent. When good talent does go on the market, it's generally pretty good at selling itself.