Planned obsolescence is a problem not just with light bulbs but the entire economic system. Of course they plan to keep phasing out and remaking light bulbs, this way people have to keep buying whatever is new to replace the old. They also make the lightbulbs in poor fashion to make people have to keep buying new ones they continue to break and fail. The manufacturers only care about their bottom line and making a profit.
The cheap bulbs do not last very long, and there's a reason for that. Corporations can make more money if they can pump out bulbs that quickly end up in the landfill. With the advent of LED bulbs, however, the trend may be changing. The expense of such bulbs, however, keep them out of the light sockets of most homes.
It is not only possible, it is easy to buy long lasting
bulbs. These bulbs cost more, but over the life of the bulb purchasers end up
saving money. Especially notable are the compact florescent bulbs that fit in
ordinary light sockets, last longer, and use less energy. Anoteher long lasting
choice is the LED light. Some LED bulbs use a tenth of the energy of an old-
fashioned bulb, and last far longer. If these fabulous bulbs do not last, you
have bad wiring!
If consumers do not wish to purchase bulbs that have planned obsolescence, they will purchase them elsewhere. There is no monopoly on light bulb production and if consumers are deeply concerned about the issue they will seek out anyone willing to develop long term solutions even at greater expense to themselves.
No, I do not think that they plan the time when a light bulb is going to go out. Now, they actually do have light bulbs that are really good and will last about five years. They just do not have the knowledge to make a bult that will never go out.