It's pretty simple if you take the view that there are only two classes in a capitalist society: those who profit from owning capital and those whose only capital is their bodies and thus profit from their labour.

The former own land, companies, and such assets that they profit from the difference in value between what is sold and the wages they pay labourers to produce that value.

Those people profit from wages going down.

One way to do that is to gain leverage over the job market by threatening to remove access to labourers. Unless those labourers are willing to accept a lower wage they can be replaced by AI and nobody will need them anymore.

Another way they can increase their profits is to force labourers to use GenAI tools to produce their work. There's constant pressure from the capital class to, "always improve productivity!" This is just another example of that.

I suspect there will come a point, perhaps, where some companies will decide to let developers go who refuse to use GenAI (or simply not hire them to begin with).

I don't know that we will see the technology become sophisticated enough to replace human developers entirely.