Because DST is the wrong time; if you look at the legal implementation of DST, most countries carve out exceptions for fields where lying about the time can obviously lead to death and destruction - navigation being perhaps the main one.

What everyone missed is that DST could itself lead to much greater loss of life than we might have lost had the use of DST been mandated all the way through to e.g. large naval, air or spacecraft.

And as research into DST continues, this seems to have been not merely an abstract possibility was missed, but _the actual outcome_. DST is quite literally killing people by the thousands.