There are still valves with volume control. In delta, for example, the '13' and '14' series do not have volume control. The '17' and '17T' series do have volume control. The 'T' means 'thermostatic' which provides accurate temperature control (more expensive). The others are all 'pressure balanced' which adjusts to pressue fluctuations, but does not control temperature as accurately.
We used a 17 series in our earlier remodel, and found that we never ended up using the volume control. In a low-flow showerhead, we ended up always having it on full-pressure. In our more recent remodel, we ended up going back to a single function (no volume control) valve. One thing I did not like about the 17 series was that the temperature control was smaller, and a bit more awkward to adjust accurately.