You always have some source resistance to limit the inrush. In the case of a power transformer, the inrush current is limited by winding resistance, core saturation, and to a lesser extent the forward conduction of the rectifier(s). Nobody purposely puts a series resistor upsteam of the filter capacitor (power wasting). Almost nobody puts a choke (inductor) there either (due to cost), although this would reduce ripple, allowing you to reduce heat losses in the regulator because you could lower the headroom needed to prevent dropout.