Yes, still true.

I have a super deluxe Asus motherboard with supposedly quite high-end Analog Devices-based sound integrated. Sounds extremely good and handles very high sampling frequences, resolution, ... if I ignore the huge amount of noise picked up. If I access an USB disk, the USB transfer will be clearly heard. And if the master volume is set too high, then the motherboard and processor will produce enough noise without external devices working.

Asus is expected to be one of the better manufacturers, and if they haven't been able to match the sound quality of a $50 low-end CD player despite having 96/192kHz 20/24-bit ADC/DAC, massive amounts of DSP power, ... in their top-of-the line boards, then it is reasonable to believe that the electrical noise levels are still very problematic.

The 286 processor in the AT that introduced the ISA bus (even if the name came a number of years later) might have consumed 1W. Several of todays chips can consume well over 100W at very low voltages. The currents are huge. A modern graphics card will then add to this - often to the point where the graphics card needs one or even two separate power connectors to draw power directly from the PSU.

Edit: The only improvement from the PSU side is that more and more consumers takes their power from 12V instead of from 3V3 or 5V. This is a big advantage, but the improvement gets cancelled by the increase from 200W to 500+W for a standard PC and kW for server machines.