Srinath -

A bit of history.
DST began during  WW I as an energy saving measure, even back 100 years ago.  When the war ended, so did DST.
DST came back during WW II for the same reason, but since that war lasted longer, people go used to having DST, so states had the option to retain it after WW II ended.  In fact states could actually choose to have only part of the state stay on DST while other parts didn't.  I recall as a child in the 1950s in Ohio that the Cleveland area up north had DST in the summer, while those of us in central Ohio stayed on standard time year around.
Back then, when drive in movies were popular, the lobby group for the owners of drive ins lobbied hard against DST, since it needed to be dark in order to go to a drive in, and the owners didn't want movies to have to wait until nearly 10 PM to start in the summer.
Slowly, DST became more prevalent in the 1970s - I think we in Ohio went for it on a state wide basis around 1970 or a couple of years later.
But I think Arizona and Hawaii still stay on standard time, as they are on the extreme western edges of their time zones and have long evenings even without DST.

Paraquat -
I think what I related is accurate.  Of course, there will always be cynics who want to blame anything and everything on some "fat cat" on Wall St.
I know of few farmers who really like DST - most of them whom I know like to get up and get going early, and would rather have daylight at the beginning of their days rather than after supper time in the evening.

Whoever came up with it did fine IMO.I like it,

Daylight Saving Time was the brainchild of the DOD. The idea was to shorten the amount of "dark time" between quitting time and bedtime,therefore reducing the amount of energy used for civilian needs and freeing up more for military/production use.

This according  to a military historian I met several years ago. Sounds likely but????