I'm of the opinion, "TV follows the trends, feeds on them. It doesn't set them. It
may accelerate them however." I'm not ready to concede that last point though. Not yet, anyways.
I really doubt earlier generations were any more honest or dishonest than later generations. I guess the best way to support my statement is to suggest reading about early 19th Century US political campaigns. They are well documented. One will see that dishonesty was as prevalent and possibly even more directed at the "politics of personality" (if that's possible) than today. It may be a bit tougher. I doubt one could get away with calling an opponent a "heterosexual" and have many voters believe the target is a sexual deviate of some sort. Not in today's world at least.
Video and phone records, public records (newspaper and TV archives), The Congressional Record, etc. make fact checking easier. Dishonesty is easier to uncover than in the past. The internet makes it much easier to spread a lie. Retractions hardly ever attract an audience. People tend to lie when it is in their best interests to do so. That, I suspect, hasn't changed over the years. Uncovering the lies has simply become easier as people leave a trail which is now readily available with a couple of key strokes.
Hell, children innately lie as self-preservation is built in at birth. Honesty must be taught and rewarded in some fashion so as to reinforce and grow that part of the personality, They learn from mom and dad's demeanor, speech, etc.,(But, as the babes age, they do learn from exposure to TV. I might need to rethink my earlier position as the TV is the "child sitter" of choice for many parents.) the necessity to lie or be truthful. When caught, they learn to lie better unless taught otherwise. Honesty must be taught.
So, I believe "Hollywood" simply uses a device, dishonesty, as one of many ways to attract an audience. No different than sex. It's simply a valuable "plot device" for increasing and maintaining an audience. Lying leads to many, easily "mined for laughs and/or drama" plots. A mirror of society and not a "trend setter" would be my position. (Which I seriously just weakened.)
I'll now concede that "Hollywood" is indeed an "accelerator".
Far too many parents abrogate their responsibilities and use "Hollywood" as a handy substitute.
Remember, "Hollywood's" job is to make tons of money for investors. They do not view themselves as the arbiter of social mores. Or, good taste I might add.