The demise of the Buffalo is what ended the Comanche nation, as well as that of the Kiowa, Southern Cheyenne and Arapaho allies. The soldiers hastened their roundup onto the reservations, but the Buffalo hunters and the killing off of the Bison herds is what sealed the doom of the southern plains Indians. The Kansas herd, roughly those Buffaloes in Kansas and extending clear into Indian Territory and extreme north Texas, were essentially gone by the winter of 1873-74. The hunters moved onto the Llano Estacado during that winter and were not molested by the US Army. The combined force of southern Plains Indians attacked them at the 'walls in 1874 and were rebuffed-and the slaughter of the Bison continued.
Quanah Parker's band surrendered at Fort Sill in 1875. IIRC, the last Indian action in Kansas was in 1878. Texas is more problematic due to Apaches in extreme western areas, but the Bison were gone by 1878 too.
The US Army was incidental. The lack of Buffalo doomed the Comanch way of life.
