I am familiar with the famous Phoebus cartel of the companies Osram, Philips and GE, but this cartel began its operation in 1924 and lasted at most to the World War II. In the second half of the 20th century and in this century too, how is it that the present manufacturers of incandescent light bulbs still use the designs that are to last for around 1000 hours (even though many competitors unbounded to the cartel arrived in present era)? (This applies perhaps to other types such as CFL - they are also near the 1000 h limit.) Is there some well documented contemporary economical argument or business plan of some company that proves that a deviation from the established manufacturing practice would result in financial loss?
Can you refer to some modern designs or actual patents (although maybe not for free use) to incandescent light bulbs of notably longer lifetime that would be said to be withdrawn from manufacture for unprofitability? (opponents of planned obsolescence often refer that these designs exist, however without evidence)
Or is the lightbulb near its design limits?
For the sake of argument, let's stick just to the class of household lightbulbs (e.g. 60 W, 230 V, 500 lm).
