This is descriptively inaccurate. The argument doesn’t assume that rural areas would have gained access to electricity if the subsidy hadn’t existed.

The argument doesn’t assume that if the subsidy benefits anyone other than those it was intended to help (like urban residents), then it has failed. This is not an assumption the author makes, nor is it the reason the author claims the subsidy failed.

This is descriptively inaccurate. The only thing that the author says about the intention of the subsidy was that it was intended to help rural residents; the author does not assume that the subsidy was also intended to help others.

While it’s true that the argument does not mention this possibility, it is not relevant. Even if it’s true that urban residents would have had trouble accessing electricity without the subsidy, the author’s argument is focused on rural residents’ access to electricity.

This is the flaw. Since all we know is that “many” rural residents don’t have electricity, we don’t know enough to say that the subsidy failed. It could certainly be true that many other rural residents gained access to electricity thanks to the subsidy, making it a success.