At least here in the USA the big freight carriers want larger airplanes, not smaller. The CRJ was made so you could have 5x daily service to midsize towns, but all the cargo arrives in one flight. Just look at the ratio of widebody to narrowbody at the likes of Fedex and UPS compared to any of the passenger majors.
For domestic air the system is already set up to get it there at the time that is required, earlier would just mean you're sitting on it waiting for daylight to begin deliveries. The box doesn't care that it has an hour layover in Dallas on the way to Midland, it still gets there by 9 am. It's much cheaper to put it on a 767 to the nearest city and meet a turboprop flown by the lowest bidder than to fuel a CRJ to fly halfway across the country.