I suspect even the more recent CFLs incorporate an hours counter (especially likely to be true when the warranty quotes 6000 hours 'based on 2.7 hours per day' for a 6 year warranty period) which deliberately blows the internal safety fuse once it's clocked the requisite hours[1] deemed to be the classic for fluorescent lamp technology 80% of 'design lumens' EoL point[2].
Although this might seem to be an imposition on the consumer to buy yet another 'light bulb' to keep the 'light bulb' industry in business (and it is), I don't have any problem with this particular usage example since it forces the end user to operate their lamps at the best TCO level in terms of per lumen production and replacement costs.
[1] A 30W CFL in our hallway failed with no prior symptoms of ageing after, by my reckoning, some 6022 hours had elapsed. That estimated service time was just too suspiciously close to the 6000 hours (6 years/2.7hours a day warranty figure) for me not to suspect the use of a life limiting counter being incorporated into the lamp's design.Of course, I'd only fitted the lamp about 18 months prior to it failing but a high efficiency lamp used for lighting a hallway[3] is going to be left on between dusk and the wee small hours of the morning every day of the year in our case so will certainly clock up 6000 hours a damn sight quicker than the 6 year/2.7 hours a day warranty implies.
[2] For the even more 'classic' linear 4 and 5 foot tubes, the hours ratings have crept up over the decades from a mere 7000 hours to around the 16000 hours mark before the design lumens output falls to 80% (a brand new tube, btw, starts off at around 120% of its design lumens output, swiftly dropping to design lumens output after only a few hundred hours of service have elapsed). [3] When CFLs first became available at a barely affordable 5 to 7 quid a lamp some two decades ago, the obvious, "No Brainer" useage was hall and stairway lighting where you'd prefer the lights to be left on for the whole duration of the evening simply for safety's sake regardless of operating costs.Later on, as these lamps became even more affordable, they'd be fitted in rooms where they'd be more likely to be switched on only when occupied, starting with the living and the kitchen and/or dining rooms before considering other rooms in the house with lower occupancy rates that had previously not warranted the use of high efficiency lamps due to the much lower ROI benefit to be gained in these locations.