Most people are basic and have basic needs, and a soundbar suffices in most cases.
I was sort of one of those people, with a soundbar, because it was easy and convenient. The soundbar came with a wireless subwoofer, and that solved the problem of running wires across my living room.
But, I had a gifted B&W 5.1 system with powered sub collecting dust out in my garage for a long time. I recently made the push to dust it all off and buy a receiver to power it, replacing the soundbar+sub we had been using for years.
The difference is really night and day. The soundbar just never got loud enough for when I wanted to crank-it-up when playing music. It was good enough for watching most TV shows, but the sound we get now from a 5.1 movie is incredible in comparison.
I did the work to run completely flat speaker wires to the surround speakers, under the rug in our living room. It took some work to re-route wires and get power to where the receiver is, but it was well worth it.
The new system goes as loud as I can stand it with crystal-clarity all the way up to "11". The soundbar looks like a piece of junk in comparison and is now out in the garage collecting dust.