I've recently learned that old bikes had HARDER brake pads that went with the steel rims. It's possible that you replaced the pads with softer pads thinking they'd brake better, but in reality that's opposite of what happens. Pads today are softer to avoid prematurely wearing aluminum brake tracks.

I've not had good luck with steel rims and decent braking performance unfortunately. My default response to people asking about it is "In most cases you can't expect the same level of braking with steel rims as you can with aluminum rims." Of course, that's a bit of a white lie. Given enough adjustment and time to play with it, you can get steel rim brakes working alright. I usually just tell people to buy a set of $10-15 rims from our shop and be happy in many ways. Many things in the biking world are sold as "upgrades" when in reality the performance benefit is marginal. An aluminum rim was not one of those things.

I wonder if anyone has ever tried v brakes on steel rims.