If the models get good enough to solve all of the low-skill problems, then we only need to keep around the people who are highly skilled. That means a fewer number of software engineers, and a difficult path to becoming someone who is highly skilled.
Agreed about the barrier to entry raising though, we're already seeing that in the glut of CS grads who can't actually get a programming job right now. Personally I suspect that this is a cultural issue more than an economic one, though. Companies need to alter their expectation about entry-level engineers and develop a culture of mentorship/apprenticeship so that advanced analysis, architectural, code review, and AI management skills are all passed down successfully.
Programmer / engineer compensation in the US market at least has been looking bimodal for at least 12 years now and the first one looks even more devastated in terms of labor than the big tech companies based upon (lack of) job postings and from browsing my connections on LinkedIn.