Actually, the Indians had already ceased to be a relevant force on the Eastern Seaboard as early as 1648 when about 95% of them died. The Iroquois barely maintained political existence ~ fortunately for them they had rights to TAKE Mingo children to raise up as warriors, and did so. The numbers were modest ~ in the tens of thousands.
Really angered the remaining Indians West of the Appalachians Fur Shur.
The wars against/with the Indians that follow 1648 reflect the rising strength of the Old World populations ~ the fact the Indians lost them all reflect their loss of strength. The Iriquois were no longer able to fight the Mohicans, and they'd had that war going for several hundred years. The conflict predated the Iroquois Confederation ~
i think Indians were better known for not even being around than anything else. They were viewed as easy targets after 1648.
The Indians might lose in the end, but they were often a menace to civilians on the frontier and could at times defeat armed militia and troops. Contrary to being easy targets, the Indians’ stealth and skill made them formidable adversaries.
The Iroquois were very much relevant until the Revolution. By 1648 they hadn’t even yet gotten started really. The height of their military power was about 1650-1666.