Hi Sergent and welcome to the group.
I don't think the scales of the rules are as literal as you are assuming. Steve will be able to tell you what he intended in his rules but I guess the designers are probably intending to represent the historical troops in a way that allows support weapon miniatures to be fielded at a different scale.
For example.
These historical troop numbers are from Mark's
Pygmy Wars siteVolunteer Army 1st Infantry Division in October 1919
Markov Brigade Major-General Tret'yakov
1st General Markov Officer Infantry Regiment Colonel Bleysh 882 bayonets, 20 MGs
2nd General Markov Officer Infantry Regiment Colonel Morozov 1,174 bayonets, 24 MGs
3rd General Markov Officer Infantry Regiment Colonel Naumov 618 bayonets, 24 MGs
Most of the rules probably don't assume a fixed scale but if we use a scale of 20:1 for argument's sake, that is 134 figures and 3 MG bases. Plus some of those MGs might be Light MGs.
These are the elite regiments of the Volunteer Army army too, so about as well equipped as you get in the war. Even within the same division we have these.
1st Division reserve infantry
Reserve Battalion of the 1st Infantry Division Colonel Konovalov 1,122 bayonets, 7 MGs
1st General Markov Engineering Company Colonel Grotengel'm 563 men
So another 84 infantry and about a third of an MG base. We would end up with model armies where nearly every figure is an infantryman with a rifle. That's quite dull and doesn't allow for much differentiation or the representation of small but significant numbers of support weapons.
For artillery it is even worse.
1st Artillery Brigade Staff Captain Shperling 14 light guns, 11 howitzers
1st Divizion Colonel Mashin
1st General Markov Battery
2nd Light Battery
2nd Divizion Colonel Mihailov
3rd Light Battery
4th Light Battery
3rd Divizion Colonel Ropponet
5th Battery
6th Battery
4th Divizion Colonel Ayvazov
7th Light Howitzer Battery
8th Light Howitzer Battery
These 8 batteries barely rate a single gun model at 20:1 and only by combining the different gun types. Yet in the historical sources we have examples of where even a single real gun could be a significant advantage.
So if we take into account the reduced numbers of weapons and historical ammunition shortages the game effect is probably much more reasonable.
For movement it is probably to do with the time scale being compressed. Real battles involve a lot of waiting about. The MG crews therefore have time to catch up and the movement is probably based on tactical movements rates rather the walking speed of the crew with their gun. If we modelled real movement rates based on uninterrupted walking we would need to have lots of very short turns where often nothing happens.
I would guess that with our 20:1 infantry scale then the rules might assume 4-8 real MGs to a base and 2-4 artillery pieces to a base.
I hope that makes sense.