converters waste power

well everybody knows that converter will never reach 100% efficiency, but now the good ones are above 80-85%. why can’t one built one with 95%? a 10% increase would do the same as either makeing the device 10% more efficient, or cutting 10% off the power uptake … or reducing waste heat by 10%

the problem seem to be the MOSFETs and capacitys inside. if you have only a few microF’s and switch at a few hundred kHz that charge is wasted – as heat. also the capacitors never give back what they got!

one should design a circuit that uses the capacitys by bouncing them around and redirecting them so that the electrons are not wasted, but ‘recycled, maybe as supply for a lower output voltage (e.g. use the 12V waste for the 5V supply)

i would compare it to waste heat from a powerplant – the temp and pressures go down, but then there are other stages that can make use of it (high press/low press turbines). some waste however will always be there, so there will be no 100% efficiency possible