The first sentence, I believe is quite self-explanatory
Prussia was, at the time, the most (or second most) powerful nation in the world when it came to land forces. They beat the entire French army in 6 months, and were only stopped from annexing France so as to keep the moral high ground and to keep their status with countries like Britain and Russia. The German empire lost WW1 due to a combination of three things--Poor leadership in Moltke the younger for the first year of the war, Poor management of international relations resulting in a two-front war (Even then knocking Russia out of the fight and ending the Russian empire), and lack of Manpower compared to the French and British, who could draw upon their colonial reserves.
The education system was Standardised long before many other countries and graduates had to join either the military or work in industry for a similar period, giving them important skills (at the time).
https://www.jstor.org/stable/2096226