I lived in Indiana when they decided to adopt DST. The reasoning was that interacting with other time zones which had DST while they didn’t was expensive. It’s bad to not use DST until none (or few) do.
Such a chilling network effect might exist if all the states were equal in population, economic activity, and interstate traffic, but that's not the case here. If California wanted to abolish DST, it certainly has the clout to pull it off--and it may very well force NV to as well in the process (and perhaps even OR and WA). Same for Texas, which could force the hands of OK/LA/NM. The Northeast would be harder; you'd basically need all of New England sans CT to agree to make the switch at once, and then NY+CT+NJ+DE(+PA?) to do so at the same. The problem is far from intractable, though.
You are greatly overestimating the cost of dealing with states that do or do not observe DST. We don’t here in AZ and it barely matters. The worst is that everyone else expects us to move around our daily stand up times twice a year so they don’t have to.
