Full time is subjective
Are we talking cover driver? 22.4? Or a full time legit driver?
Also, many hubs or package service centers do not offer full time hours.
Some hubs do offer split shifts for what amounts to 8 hours (all inside non driving work).
Anyways. My area had a drive wait list of 5 years just three years back. But ever since then, some new guys have started and went to drive within 2 months. I want to say they're combo guys and their first 3-4 months were brutal, sometimes not even driving for weeks. Many still don't have their own routes. They may be set to be 22.4s for life. I don't know
Each area differs. Just a city south of my metro, they take off the street hires and turn them into legit drivers within days (the driving test, driving school, physical part all take longer).
Bottom line, there is no easy answer.
Split shift bids rarely go up. For my area, it's easier to get the 22.4 ft hours than trying to stay inside and wrangling yourself a 40 hour week.