EDIT: s/your/my/, s/you/I/ ... my personal position may not be best for you.
If you really are bringing the same value to the company, then 50/50 is correct. In reality, that's not likely to be the case.
The CEO needs to be the guy that holds it all together. That's a lot of responsibility, and requires some serious knowledge/education/experience/talent/etc. As much as I like to think the developer is the lynchpin in the company, it's actually the CEO. A bad CEO will destroy a company faster than a bad developer. And a bad developer is easier to replace.
As the article says, the split will depend on the people involved. There's no magic formula for figuring it out.
The article does not say that 50/50 makes sense if and only if you bring equal things to the table. That's an unequal split argument in disguise.
Out of curiosity, do you want a larger stake because you want more money, more control, both, or for some other reason?
To be fair, that smaller share sees me shouldering less responsibility, too, though. While I'd still be critical for the company to succeed, there's a lot of problems that just wouldn't be mine to shoulder.