The easiest and most obvious answer is to say a 45 minute episode without commercials allows for more plot development and more room to tell complete stories within an episode. But dramas used to clock in at 30 minutes or less than whether it be a detective noir show like Peter Gunn and or a western Gunsmoke, which was originally under 30 minutes. So did dramas also take on an hour timeslot for ratings and its just remained out of habit? And with the rise in binge-watching, would you want to have shorter shows so that it's presumably easier to absorb more episodes at once?

I think that's why nearly all non-comedy shows are 1 hour long. Unlike with Sitcoms where the stories can be tied to together within a 30 minute span, dramas and westerns usually have more complex stories to tell which require 45 minutes instead of the usual 23-24 minutes you'd get with a sitcom. The examples of Peter Gunn and Early Gunsmoke and perhaps even Mr. Lucky are all tv shows that premiered in televisions early days and I think dramas and westerns going to the 45 minute format was a sign that the stories were becoming more complex and longer.

As for the binge-watching, I don't mind if a tv show is a longer one. I'll binge watch Gunsmoke and The Rockford Files,for example.

I think it's difficult to tell a compelling dramatic story in a 30-minute time slot. Certainly sitcoms manage it, on Very Special Episodes, but it seems far easier for dramas to have a longer run time.

Back in the 1940s and 50s, there were attempts at having 15-minute shows, but they fell out of favor. Netflix recently revived this format.

I think the addition of melodrama to nearly every show has made it difficult to present a taut story. If Dragnet was done today, Sgt. Friday would have a will they/won't they relationship with Officer Dorothy, who will be frustrated over not being taken seriously in the workplace. Bill Gannon would be a recovering alcoholic whose beloved wife was murdered by a street gang. Good luck dealing with that AND breaking up that purse snatching ring in 23 minutes.

I really think that you've "nailed it" there. Attention spans are so short, and people unable or unwilling to focus their attention on an indepth plot (the ADHD thing) producers have found that by really telling 3 stories at once, they retain a larger audience from channel surfers who are mostly looking for immediate gratification.

the movie "Pulp Fiction" is probably the best example of this, albeit perhaps a bit overdone. If you watch it through to it's conclusion you can eventually determine how all the disjointed segments fit into the main plot. While at the same time they are putting plenty of ~toys over the crib~ to amuse those who have no intention of distilling the plot.

On the subject of TV show run times, the older shows are the best because there were fewer commercials back then and hour long shows ran 50-52 minutes and half hour shows ran 25-26 minutes.

I think the addition of melodrama to nearly every show has made it difficult to present a taut story. If Dragnet was done today, Sgt. Friday would have a will they/won't they relationship with Officer Dorothy, who will be frustrated over not being taken seriously in the workplace. Bill Gannon would be a recovering alcoholic whose beloved wife was murdered by a street gang. Good luck dealing with that AND breaking up that purse snatching ring in 23 minutes.

Yep, when the half-hour drama/action shows started expanding to hour length in the early-1960s, it wasn't so much that the plotlines expanded, but the extra time was given over to characterization. A sort of merging with the NYC-based 'live' drama series. In theory, this doesn't sound like an inherently bad thing. But new crops of writers started re-defining 'drama' and characterization through a psychological prism, where everyone is either crippled by or motivated by past mental demons, and all relations suffer from dysfunction. It seemed to inflict just about every genre eventually. Instead of good, crisp tales, we got naval-gazing and the wallowing in inner psyches. Emotionalism and melodrama, with the side-effect of cultivating an inward-looking self-absorption in the culture at large, and all the unwelcome noxiousness that this has entailed.

While I admit I might still have occasional affection for some such shows, in retrospect I can see how they were early signs of society starting to go off the rails. Wearing far better have been those earlier, unpretentious half-hour shows in the "Dragnet" vein. Clever, creative yarns spun to fit a 30-minute timeslot. No psychiatrist couch pity-parties. No ham-fisted social agendas. Just straight-arrow style conflict/resolution, with genuinely adult professionalism and comportment. No angst, no whining.

There were a few soap operas here in Sweden back in the 90s, who had 30 minutes long episodes.
This died out very soon after the beginning of the new millennium though.
And nowadays, I believe that only shows for children or teenagers will have such short episodes.