[MisterTea]

Dumb DC supplies using just a bridge rectifier and filter cap(s) isn't really ideal if you need a stable voltage. If the mains voltage sags, so does output. Then factor in ripple from the cap bank under higher loads and the associated nonlinear harmonics and power factor issues from the rectification. You could add a linear regulator and increase the transformer output and burn the excess off as heat but efficiency goes down the toilet.

Switchers, for all their complexity, are pretty damn clean in terms of output and input PF correction. Even in audio and sensitive analog applications where dumb supplies were preferred have been replaced by switchers. A good design goes a long way and it's unfortunately easy to design junk switchers because of the complexity involved.