Actually there was a lot of that going on int he late 70 and early 80s.
I fondly remember a Cosmac (several) doing very good music with only a
transistor and speaker off the Q output. They shared a common heartbeat
using EF lines to keep the music in sync across 4 fairly simple 1802 boards.
(they had more memory than an elf and small rom likely UT4). That was
PCC76 in philly.
Of course there was a half dozen other using S100 and various soundcards
of the day that took that several notches up.
Heck my PDP-11/02 (LSI-11 cpu) has a Gigolo (DEC internal build, never sold,
for various DECUS and other events) card (two channels) of sound
based on the AY-mumble sound chips of the late 70s,
Another system I worked on for a company still in use for process control
for a production line has a Cromemco Dazzler color video card from 1976
in a S100 crate.
One of the system I still use a Visual 1050 uses a 6502 for the CRT
rendering (monochrome, 320x240) graphics and text as a slave to the Z80.
That runs CPM+ and DRI GSX/display manager.
So music and graphics are not PC new. If anything it took a few years for
PCs to catch up to that. I think we forget that. During the between times
before the PC (and others) was the dominant graphic engine the Amiga
was the hot machine. Maybe many don't remember the workstation wars
( 1Megapixel display, many megabytes ram, and 1 MIPS (1 million instructions
a second) of the mid later half of the 80s (pre 386cpu).