If you look at the rear of some receivers they are jam packed with speaker terminals, analogue and digital inputs and outputs, HDMI ports, USB, etc.
The bulk of the receiver isn’t really an issue to those who still prefer to use large-ish hi-fi speakers, rather than following the trend of small mono speakers fed lossy audio over Bluetooth or wifi.
Personally, I’ve never liked the ‘tiny speakers plus big boomy sub’ sound ever since it became a trend in computer speakers, and most sound bars just continue that idea.
Also, why is there never the option to turn up the center channel contribution when downmixing surround formats to stereo? Many sound bars are plagued by excessively quiet dialog when playing back certain content. A big bulky AV receiver is likely to give you a lot more control.
This is compounded with the newer super bright LEDs. I've got a Asus chromebook that lights up a dark room every couple of seconds when it's charging. It's served as a great beater laptop for the past 5 years yet that LED has never once been of use to me but pissed me off dozens of times as I've had to get out of bed to cover it when in a hotel room somewhere.