SMPS sure have their advantages and nowadays you will not see any PA amplifier without it. But their reliable life time is limited, usually to about 10 years. For Pro PA not a problem at al, as it is their usual service life too. But for private home use, recapping after 25 years is normal. Regularly swapping SMPS? I doubt.
Some posts earlier the Perraux amplifiers came along as a kind of reference example. These are beautiful amps. Despite the design is rather simple, they have precise and smooth mids and highs and a huge bass drive. Nevertheless they are never fatiguing and almost indestructible. Recently I did restore a over 25 years old 3370 model and a 3400 model Perreaux, rated at 300W_rms continuous. I considered also putting a SMPS into it. But as they are, these beasts can spit out over 25 amps at 80 V_peak for short burst periods, thanks to its large rail buffer caps. That is more than 2 kW peak! Hard to find a suitable SMPS of plus and minus 90V that can deliver that peak power and fit. So I left the heavy tranny at its place for another happy 25 years