This is correct in the sense that, if you were to build a zero emissions energy system from scratch with today's technology, your conclusion would be that you'd eventually have to do this.

But in much of the world, setting up PV is economically sound simply because it displaces a certain amount of kWh generated over the course of a year from other sources that are more polluting and more expensive.

In this regime, the dynamics of production over time don't matter yet.

At some point, when renewable generation has very high penetration, you'll reach a point where building more is uneconomical, and to then displace the remaining other power sources you'll need to overpay (ignoring externalities).

However, that's assuming no technological change on the way there, which is a whole separate topic.