Going back to the Italian doctrine of the summer of 1940.
The Italian Army developed a new and revolutionary doctrine of combined arms warfare in 1938 based on the lessons learned from their experiences of the 1930s. The success from the use of Italian combined arm teams in Spain and in Ethiopia proved the concept of motorized forces and the natural follow-on of mechanization for the Italian Army. This doctrine was called the War of Rapid Decision. With this doctrine the Italian Army had developed a new and dynamic operational art of war. The Italian military in Libya had all the necessary elements to be successful utilizing this new doctrine. In addition it had a commander that already successfully used and demonstrated an applied motorized doctrine in the Italo-Ethiopian war where it proved victorious to him. Marshal Graziani didn't utilize this new doctrine.
Combined with the available armor and motorized artillery forces, he would have had a potential mechanized force to invade Egypt with in August of 1940. The only realistic motorized formation that could have been formed is with the Comando Carri Armati della Libia, possibly three or four artillery Regiments, and one motorized infantry division.
As far as the Italian tanks needed to implement such a doctrine, the two battalions of M11/39s (72 tanks) were sent to Libya in July 1940 becoming part of the Comando Carri Armati della Libia on Aug 29th 1940. These tanks formed the backbone of the advance to Sidi Barrani starting Sept 13th. As mentioned earlier, most accounts say that these tanks had no radios.
There were a few radios in special command L.3/33-35s, maybe one per company. Italian training was rather sketchy. In the summer of 1940 there were only 1 or 2 tanks larger than the L3/33 or Fiat 3000 in the tank school/s and even at the short period of 25 days most trainees only got a limited amount of driver, gunner, and mechanic training.
The M13/40 was in production but the low rate of production meant that the third medium battalion (III/32) arrived in Libya in Oct with 37 tanks and the 4 battalion was sent to Albania in Dec while the 5 battalion was sent to Libya. Only 1 or two went to the tank schools so training was woefully lacking. While it was planned to have radios in the M13/40, just like the M11/39s. lack of radios meant that few, if any were installed as built. The 6th battalion was sent at the end of Dec, 1940. It was not until late spring or early summer of 1941 that the M-13/40s got radios fitted at the factory in large numbers. The L6/40 was ordered into production in March 1940 but no production examples were delivered until May of 1941 (?).
This is one leg of of the combined arms doctrine and as can be seen, it was a pretty shaky leg.
The infantry component was also very shaky for use in North Africa. Combined arms in the Italian Alps or in Albania don't need the amount of trucks that North Africa does and with the main tanks maxing out at about 32kph on a level, decent road, fast trucks are not needed either and perhaps the
Bersaglieri could have been used for short movements (2-3 days) in poor terrain? But trying to move without trucks in the dessert over long distances in an area is scarce resources (water and food) is not going to work. Trucks do have stop further from the battleline and have the troops dismount but than can be taken into account in in 1940 (nobody had APCs). Having radio links between the tanks and the infantry was very important. Motorcycle messengers are not going to work.
And that brings us to the 3rd leg of the stool. You need artillery and for fast moving battle this means you can't use standard artillery tactics/movement or even strength (numbers).
In WW I it was hard enough for the artillery to try to keep up with the advancing infantry, granted trying to use horses to move even light artillery over shell torn ground was extremely difficult. With even slow tanks things got rather difficult quickly. Even a light battery (75mm guns) can take around a 1/2 hour to unhitch and get into position. They were no long riding into position at gallop, unlimbering and blazing away with open sights at a visible enemy like 1914. The guns had to placed into position to shield them from return fire (at least the reverse slope of a hill) but in place that could be located on a map, survey stakes had to set out and aiming markers put out. Calculations made as to likely targets on the map and the guns, especially those with limited travers, aligned accordingly. Radios and/or field phones set up. Now imagining doing that while trying to support a tank unit that was advancing even 3-4kph. They would be out of range in about 2 hours assuming that the guns started about 2km behind the start line. You have to leap frog the batteries so there are always one or two batteries ready to fire while the other battery/s are moving. When it is time to move the survey stake and aiming makers have to picked up and stowed. Ready use ammo made safe and stowed. Communications equipment stowed (field phone wire can be left, assuming there is a stock available, for clean up crews) so there is a lot of things to do besides hooking the guns up to tow vehicles. Trucks allow for the artillery to follow tanks down the road but the tanks can start and stop much faster than the artillery can. Going off road can leave the artillery bogged down in soft ground.
Longer range artillery can cut down a bit on the leap frogs (12km range guns vs 10km range guns?), guns with 60 degree traverse are much quicker to set up than guns with 6-8 degrees of travers.
Outrunning your HE and Smoke support can be deadly for both the tanks and the infantry.
It is easy to write about combined arms doctrine in the abstract and you do have to start somewhere. But there are dozens if not hundreds of details that have to worked out and in Aug, Sept, Oct 1940 Italy did not have many of pieces in place. British also did not have combined arms doctrine in place but they had more working radios, better trained troops, and more trucks to improvise with.
