For one example, the article says that some of the best value that a business co-founder can contribute is disproportionately building the relationships. But those relationships can be more connected to the business cofounder themself, than to the company.
It's a bit different for the technical co-founder, since your perceptible contribution is usually IP expressed in in artifacts like code that is owned by the company, and can't legally be taken with you.
There's also the perception of the value of that IP: much like a novice programmer might think that most of the value is in their own software/knowhow/grind/brilliance, the novice business person might think most of the value is in their own ideas/leadership/network/hustle/brilliance.
The business person might also perceive the technical contribution as being commodity skills, and ones that can increasingly be done by "AI" robo-plagiarism for $20.
So, if the business person is, say, having second thoughts about the 50/50 split, they can make a backroom deal with investors to cut out the technical cofounder, or bring their new relationships with investors and/or customers with them to a different (or 'different') startup.
Obviously, one defense is for the technical co-founder to somehow be a superhumanly valuable non-commodity, and to make sure that the business co-founder understands that.
But, realistically, doesn't the technical co-founder probably need a lot of trust in their character and commitment of the business co-founder? Maybe even more than vice versa?