Why is most music today follow a math cadence? Then add rhyming? Are artist today really that bad they have to resort to that instead of it natural stuff?

What happened to the days of where somethings did not rhyme but was plugged with another word? Like Johnny Cash, Journey, Frank Sinatra, Dean Martin and others. Even if they did it it doesn't sound so blatent. Did Mozart and Behtoven do it back then?