I'm going to respond by challenging the premise of the question.

Songs, chants, pageantry, etc, are, as you note, not really staples of North American professional sports. There are exceptions, specifically within the soccer community mainly of course.

Songs, chants, traditions, and pageantry are huge staples of North American COLLEGIATE sports though, specifically in the United States.

If you go to Madison, Wisconsin to Camp Randall Stadium to watch the Badgers play (American) football... you better ready yourself at the end of the third quarter. Because that's Jump Around Time, where the PA plays House of Pain's "Jump Around" and the entire stadium literally shakes as half the stadium (and entire student section) loses their minds and jumps and sings to the song.

If you make your way down to Baton Rouge, Louisiana for an LSU football game, you'll (maybe) hear the student band at various points break out into a catchy song called "Neck" that then leads to the student section loudly inviting you to, ummm... perform a sex act on a big cat

If you head back up to Ann Arbor, Michigan for a Michigan Wolverines game, at some point during the game 100k people for some reason are going to break out into singing "Mr. Brightside".

In Tuscaloosa, Alabama, the Crimson Tide's students revel in singing "Dixieland Delight"... by the band Alabama, of course. Like you do.

That's just a small sampling. There's also then of course the fight songs and alma maters that are sung at each and every school (Georgia Tech's fight song "Ramblin' Wreck" famously features the lyrics ' To hell with Georgia' -- their cross-state rival). Even though it's not an official school fight song, you're going to hear "Rocky Top" (a song about moonshine, of course) about 36926 times during the course of a Tennessee Volunteers football game... to the point where it is often mistaken as the school's actual fight song.

Then there's the chants. "BOOMER. SOONER" in Oklahoma. "ROCK. CHALK. JAYHAWK" at Kansas. Even the simple "GO GREEN. GO WHITE" that alternates between the sides of the stadium at Michigan State University.

This is a lot of words to say that the pageantry and tradition (singing and chanting) you're asking about are in fact all there in North American sports. It's just at the collegiate level. And in North America, collegiate sports are as big or even bigger than professional sports in some regions. NFL professional football stadiums in even the largest markets basically have capacities of 50,000-75,000. But NCAA collegiate stadiums in odd places like Knoxville, TN, Ann Arbor, MI, and State College, PA all hold over 100,000 fans on gameday.

Now, if you're wondering specifically why there's little singing and pageantry on the professionalnal sports side... I honestly am not sure, and that's a different answer for someone to tackle But they are ever-present at the collegiate sporting events across the United States all year long.