For the last few decades, it seems that most shows (dramas, not just comedies) don't put the episode titles on the screen. Does anyone know why not?
My theory over the years is that people would remember a title better than they might remember the first few minutes of a show (usually before a distinctive plot might pick up), so the chances of the audiences watching a potential rerun are higher. A good example of this would be The Simpsons, where the first act of an episode rarely connects directly with the second and third.
I would think it's mostly because the shows has grown shorter to fit more advertising into the time-slot. Something has to give, so the prioritize the actual story over a long title-sequence and/or more explicit intro of each block (ie. an establishing-shot of a known location from the show, rather than a title-card with "The ... show continues". It's also worth noting the obvious exceptions to this rule... like "Game of Thrones", which has a very long and elaborate title-sequence - as well as 1 full hour episode, rather than the usual 40-45 minutes of your typical "1 hour" show... of course, GoT runs on HBO, which is pay-TV and not advertising-financed (so QED :-)
Another thing is that also the seasons have become much shorter. A full season used to be 25 to 30 episodes... today it may be as low as 18 for a "full season". Those to facts - shorter episodes and shorter seasons - doesn't leave much time to actually tell the story.