Do artificial light sources cause enough fatalities in light-attracted insect species to cause eventual extinction?
Short answer:
Yes, it is highly likely that artificial light sources may cause such high mortality that insects become (locally) extinct.

Long answer:
As you will understand, it is almost impossible to perform an experiment where lights cause extinction of a species. However, we have a lot of 'circumstantial evidence'; cases where it is clear that lights have dramatically decreased species richness (which means local extinction). If lights can cause local extinction, they can also cause global extinction if, as in your question, their entire population would be exposed to light.

Percentage of insects attracted/killed by light
Why insects are attracted to light remains unanswered, but that they do is clear. Also, it is known that insects that are attracted suffer an increased mortality, due to the light itself and due to predators actively hunting the blinded and inactive insects. The reported estimates of the number of insects that are attracted and killed by a light source differ and depend on the light source (color mainly), the background lighting (moon!) and other factors. A fair estimate is that about a third of the insects that are attracted by a light source are killed
A third is a very high mortality, that is off course added onto the other (natural and man-made) mortality insects suffer from. It is very likely that this would cause insect populations to become extinct, especially those already at risk.

Based on observations
Eisenbeis&amp;Hänel give a number of examples that show that insects populations dramatically decline when exposed to lights:
- the number of insects drawn to the lights of newly build fuel stations is high in the first years, than rapidly declines.
- the butterfly fauna in remote Austrian valleys declines after introduction of lighting (for tourism).
- The number of caddisflies drawn to lights exceeds that of the number found in a stream.