How come Military Superpowers are always viewed as failing to adopt to guerrilla warfare/insurgencies?

Britain defeated the Boer commandoes,who were conducting a guerrilla war from March 1900 until the end of the war in May 1902, and the Communist guerrillas in Malaya during the Malaya Emergency of 1948-1960. Both times,the British military adapted to the terrain,the enemy tactics,and the situation to eventually win the conflict.