Actually in terms of musicianship the bar continues to go up. We have many of the best musicians the last century alive today, because with exposure the competition has become way easier to see and mark yourself against. The skill level is incredibly high, I mean just look at guitar players and lead abilities.
The studio has become a crutch rather than a tool, an instrument to be mastered to complement a great arrangement and composition. On the whole its really hard to gauge entertainment. However when you break it down, somethings become obvious.
For example, you can always do the age old test of having someone perform a song acoustic. If the songwriting is really on point, the melody is strong, theyre tying together good phrasing, combining things into a real composition with good arrangement... Its going to show through with just a voice and a guitar. Doesnt work for all genres of course, but it still illustrates what the studio has become and how produced things are. Only a few short years ago EVERY SONG was produced like it was made to be in Disney cgi movie about two parrots, because it probably was. It became a huge hit because of promotional tie in for the movie. Its all deep tympani, with huge choruses of people in the background NOT harmonizing and just singing the main line of Ohh ohh ohh
Havent tou noticed every Katy Perry song has that part where she just blindly goes uh oh oh oh, uh oh oh oh? Roar, California Girls, all those trash songs have it.
There are some great performers out there, but songs like Adeles Hello wouldnt have been a hit without her clout and powerhouse voice. The main vocal melodies are soooo boring and meandering.
Songwriting has plummeted, production is king. Live music isnt dead but damn hardly anyone really does it really well among the top echelons of stardom.
Speaking as a working musician who gigs every week, its clear which songs people like to have heard in a bar and which are classics. I know, because they make me money lol. Some of these artists would do a lot better if they werent forced into boxes by themselves or others, Ed Sheeran can probably write some really good deep tunes, but are we going to hear them? Probably not over the noise of the monster hits. Not gonna claw my way through a record for that
Despite everything I've said these are some good points. But this speaks to me about what is trending more than what is available.
I think a key difference with today vs yesteryear is that back then, you were kind of just stuck with whatever was popular. You had a radio, you could watch tv, you could go to local shows. That's it. But now you have unfettered access to all music being made the world over. That's an insane difference.