> the cost of electricity used by the bulb is easily as much as the replacement bulb
This point is only relevant if 1000 hour old bulbs cost more electricity to run than new bulbs. Maybe I don't understand how old bulbs worked but why couldn't they invent ways to make bulbs run hot which also last longer than 1000 hours.
Light bulbs die because the filament slowly evaporates. If you increase the filament temperature just a little, efficiency increases quickly and life expectancy decreases quickly. They were already using the most heat-resistant metals, too. It's not sabotage, it's physics.
This point is only relevant if 1000 hour old bulbs cost more electricity to run than new bulbs. Maybe I don't understand how old bulbs worked but why couldn't they invent ways to make bulbs run hot which also last longer than 1000 hours.