Question

Why are TV shows nowadays so boring?

Answer 1

TV show producers create shows they think are entertaining to people and will get the most rating from their viewers.

Answer 2

The answer is a matter of opinion, and you're going to get different answers
from different people.  Here's my take on it:

The writers, producers and advertising sponsors of these shows certainly
don't think they're boring.  And definitely neither do the TV networks that
decide which ones to broadcast. 

I'm not trying to say "The experts don't think they're boring, so you must
be wrong".  I'm trying to say that different people have different opinions
about the same shows, and in your case, you find them boring.

My conclusion is this: 
I think you're finding TV shows boring nowadays because you're growing
as a person.  You've grown, developed, and matured to the point where
you're above the level of audience that the shows are pitched for.  That's
a very good thing !

You're sad because you used to get pleasure and entertainment from TV,
and now it doesn't give you those things.  That's like losing an old friend,
that you used to have such fun playing with, but he just doesn't do it for
you any more.

Now that you've grown up, you've made new friends.  With them, you do
things that you wouldn't even understand with your younger friends.  And
you develop new interests, like ... I don't know ... books, movies, hobbies,
your church, your profession, learning new things, developing new skills,
exercising your brain, writing, volunteer work, ham radio, building fine
furniture, singing, learning to write music, raising tropical plants, sculpture,
politics ... whatever turns you on.  Some people never grow past the stage
where staring at the tube is all they need in life, because they don't have
what it takes to be interested in anything else.  Those are the people that
TV is aimed at.  But you have more, and that's why TV isn't enough for you.

There are other possible reasons why TV bores you.  But until I know more
about you, I think it's a very, very good sign.