It barely glows. The "lightbulb cartel" was basically a consumer protection because barring major inventions, any deviation from the thousand hour lightbulb would have severe drawbacks in terms of power efficiency or light output.
The free market is designed for this. If the bulb lasts 5000 hours, but burns 1/2 as bright, consumers can easily decide what they prefer.
And further, the cartel did not have exceptions for product enhancements, or improvements, which might have enabled > 1000 hrs without any drawbacks.
Why are people defending this cartel? Market collusion is generally frowned upon.
The standards were set around what could be sold as a standard lightbulb.