In my opinion Christensen wasn't talking about outsourcing your entire development process to a competitor with much deeper pockets, giving them the ability to turn off your development at will [1], and then running rings around them. I'm sure you're familiar with his story about Dell and Asus. This is worse.

[1] Unless you're assuming that you maintain control over your technology while outsourcing most of the development thinking to a rented AI? Times have changed, and the API is not the only issue anymore.

What is the issue? Local models still exist and will continue to exist, and even if they don't, good old fashioned hand coding will never go away. The point is even AI companies are run by people and one company cannot make every product well, there are always gaps in the market that are exploitable.