Based on information I've got available, carts during the Classical and Medieval periods -- the primary tool of logistics -- would have moved at between one and two mph, depending on the condition of roads, and much slower where roads are not present. Infantry could manage between two and three mph marching, depending on road conditions, but would outrun logistical support unless forward supply bases were available. Cavalry forces could maintain speeds of five or six mph, but would also run into logistical problems quite rapidly -- however, less reliant on roads.
For the Roman period, where I have more data on hand, the Rome-Antioch journey could be undertaken in one of two ways -- a journey mostly at land, or mostly at sea. At sea, using the expected speed of 1 knot, or roughly 1.5mph, it would take, on average, 55 days. The mostly land journey would require about 124 days.
HOWEVER, this misses the significant disadvantage of the ship, namely, that it can be held up in port by contrary winds, poor weather conditions or maintenance for weeks at a time. The winter months were also entirely unsuitable for sailing, and generally saw ports closed and ships docked. Troops would also tend to arrive in poor health after weeks afloat in terrible conditions, and often required one to two months of time to return to full combat readiness, gather material for the campaign, and generally stop having vertigo. And there was always the risk of a major storm wiping out the entire force, as happened many times during the first Punic War. The annals of British and French naval history recount similar episodes, where troops disembarked on Caribbean islands or the Indian coast would arrive in poor health, only to be ravaged by disease and enemy fire not long after landing.
So, while Civ naval transport isn't as fast as it could be, it also isn't nearly as painful as it historically was. If ships were regularly subject to disease, storms and the myriad other issues that plagued them, it would behoove us to make transport more powerful as a result. Since they are painless, we are under no such obligation.