Yes, they can.

Main marketing push is efficiency. Yet beyond good Bronze PSU it is questionable, beyond Gold it is stupid.

Rising efficiency means that you need to reduce losses in elements of PSU.

Bronze PSU do this by going from group stabilization to DC-DC converters for 5V and 3.3V. Good Bronze PSU can have very high efficiency and use elements (mostly MOSFETS) designed for much higher load to further reduce losses.

Gold PSU is doing efficiency improvement mostly by switching to so called LLC resonant half-bridge scheme (some PSUs even use full-bridge to gain 1-2% more efficiency).

Further progress requires to put even more beefy elements and ... actually reduce voltage quality.

Main savings start to come from reducing number of transistors switching events. The lower the PWM frequency - the higher the ripple voltage (you can compensate it with capacitors, but still).

It is much better idea to put nice good heatsinks (very cheap extruded alu) and high quality fan and reduce it's speed a lot where possible.

But in reality we have huge marketing expenses, certification costs, stupid idea of half/full passive modes, Japanese capacitors craze and much more of such shit.