Since EMS in Worcester is run by UMass Medical Center, it's their responsibility to provide the radios. My guess would be that someone in purchasing sat on the purchase order request a bit too long.
Apparently today was the switchover from the old EDACS system to the new P25 trunk for Worcester city services and fire. Worcester EMS is included as well, but someone forgot to fund radios for them, so they're working off a single portable radio per truck until the new hardware can be purchased and installed.