Cabovers fell out of favor for a number of reasons, but mainly due to relaxation or changes in overall length restrictions.
You’re 100% right on why they stopped, but they’re also an absolute pain to work on the engine. In high school I worked at the shop of a trash company owned by a guy at church; the Internationals you just popped open the hood and had maintenance access for days; the Mack’s for picking up dumpsters you had to tilt the cab forward and it was, shall we say, an adventure to access the front of the motor.