I had the same problem, other than I don't share a water line with anyone... I have my own well.
I have 4 outdoor water sources; 2 spigots and two "Iowa Standard" drain-back hydrants such as you have pictured. One of the hydrants had low pressure, everything else, including the pressure in the house was just fine.
The shutoff valve for a drainback hydrant is well located well below the frost line, approx 4' in Nebraska. The rod that opens and closes the valve is actuated by a long brass rod connected to the handle linkage by a set screw.
My problem was the set screw had loosened just enough to allow some slippage between the handle linkage and the valve actuator rod. Even though I would throw the handle fully over to "full on", the slippage in the linkage was only actuating the rod no more than if I had turn on the hydrant to 1/4 full.
I readjusted the linkage, retightened the set screw, and "Voila!"... water pressure!

Gadget