I adopted Pulseaudio back when it was still called Polypaudio, so I am aware of the problems of Linux audio before it, but PA was just yet another sound server in a world that was already full of them and didn't really bring anything to the table. Linux audio world is exactly as much of a shitshow today as it was before PA. Lennart didn't even envision people writing the PA API directly, but rather going through gstreamer (then a fancy new thing) or the like.
Pulseaudio got popular and then became "irreplaceable" because it started playing a role that would have been played by HAL back in those days; i.e. setting up audio policy (routing, etc) whenever the kernel would fail at it. I was very critic of Pulseaudio, a sound server, incorporating this role, and argued that this complexity would make this project impossible to replace with a newer sound server when it inevitably came. I was proven wrong, albeit in my defense the replacement Pipewire did require a shitton of effort, and PA was becoming toxic in the meanwhile (see the Bluetooth codecs drama).
Pulseaudio's "big" technicaly improvement ("glitch-free" audio, aka interrupt-less, long buffers), and without a doubt its major cause of annoyances to users (since it exercised a lot of rarely used APIs), has not been adopted by Pipewire (which goes back to "low latency" + lots of interrupts) or any other sound server for the matter. (And Pipewire still manages to have better performance...)