Rodan: ATC wouldn't necessarily provide RAS all the time; at my airfield the density of known transit traffic means that on occasion we only provide RIS when circumstances permit eg instrument approach in VMC. Commercial air transport pilots seem to be happy with this, especially with the advent of TCAS, even if the transit is non-squawking.
One advantage of a class G ATZ over a class E CTR is that a clearance and 2-way comms are not required in class E airspace, whereas they are both required in an ATZ notified as ATC.