Actually Europeans wouldn't have gotten a foothold here without their assistance. Initial colonization attempts routinely failed, the English starved while looking at rivers teaming with fish, water being somewhat toxic back home. They learned, eventually, and 70% of agricultural species we consume today came from Native Americans.
Colonial powers battled each other, in fact, if it wasn't for such a distraction in the Caribbean taking soldiers away (as well as poor planning), the Brits may not have lost the American Revolution. The colonists, as we all know, used warfare tactics learned from Native Americans. If it wasn't for that, they would lost against that superior military.
The Europeans had guns but more importantly disease. Technological capability is great but that tends to not do as well when you have to wait 5 months for resupply.