Id answer this question, with another question.
What skills are jobs your looking at asking for?
I wouldn’t really worry too much about the $ per hr you get if your on salary. The calculation is more of a rough estimate, as if your on salary you could end up working more, or less than 8 hours a day for example and your still getting your salary. There’s also benefits, retirement help and other “perks” like free food, or working from home.
I wouldn’t also thing there is 1 single skill that magically gets you more money in a company. There are too many variables, like the company itself, your starting pay, the “perks” I mentioned, how well you work, what kind of work your doing, if there is even budget to pay you more (you could be doing great and get laid off). The list goes on and on.
Finally if your looking for a “quick and sure way to retire in X amount of years with X money” I would stop, and consider your motivations. If your choosing a “developers” path for just financial reasons it isn’t wrong, but it could be totally not worth it, and not for you. I’d only be a software developer if you like it, or at least tolerate the work. I believe everyone can learn how to code, but not everyone can code for a living. On top of that, the easiest way to “get more money” is to go into management, but that usually increases ones stress dramatically. All of this should be considered.
There’s a difference between fun and games coding, and bashing bugs on weekends because you like it. If you like what you do, and you put in the time, you will get a pay raise if you push for it. Even if your job sucks, you can push to get a better job. As long as you put in the time to get the skills necessary for “the better job” the sky is the limit. But as I mentioned, you gotta tolerate putting in the time, it isn’t a situation where you can learn X and achieve all your goals.