In technological advantage, practically none. Native warriors were equipped with muskets, just like the men in the British and American armies. They did have a harder time organizing logistics and supplies, and their semi-sedentary lifestyles typically meant that their villages were undefended, and were often the targets of small, quick raids that burned their fields. They could not supply their own ammunition or replace lost or broken parts for their muskets - but remember also that the British in the mid 18th century fighting in North America were reliant on constant resupply from Europe to sustain their efforts in the French and Indian War, and the American troops in the War for Independence similarly had very little home-grown industry for producing their own weaponry, and depended on the timely alliance with France to sustain the war and refresh their materiel. Native forces, in the Northwest Indian War, relied on British trade for the same.

Although the Native forces lost, it's important to place it in context: the Battle of Fallen Timbers, for instance, was a brief skirmish with few losses on either side, and it followed on the heels of two disasters of the United States army, under Josiah Harmar and Arthur St. Clair, respectively. Warfare is an exercise in both sides looking to maneuver the other into a position where they can wield their advantages best against their opponent's disadvantages. Harmar and St. Clair were defeated on chosen ground, in surprise attacks that bypassed fixed defenses and neutralized the American advantages in cohesion and discipline.

When Wayne eventually defeated the Wabash Confederacy, it was because he avoided open battles, made sure to strongly defend his supply lines in fortified supply dumps, and only ever offered battle in times and places where he had distinct advantages. In short, the United States won not because of "better technology" but because of a massive commitment of time and resources and a commander willing to think long-term.

There are even arguments that the Wabash Confederacy wasn't necessarily defeated because of the Battle of Fallen Timbers, but because of the perceived betrayal of their interests by their British allies. Gaff's Bayonets in the Wilderness sums up the argument fairly well. For my part, I more or less agree that US force of arms was not the primary factor in ending the war.

However, we should address the fact that, culturally and economically, the United States was able to concentrate a great deal more of their power in winning the war against the Wabash Confederacy, but the issue was never inevitable. Indian wars were expensive, and the length of Wayne's campaign, following as it did a stupendous loss of life in St. Clair's defeat, was constantly at risk of being concluded prematurely, and Washington's wisdom in pursuing and sustaining the war was called into question frequently. Washington himself was not always the firmest supported of Wayne, and even Wayne had to deal with the sometimes comical efforts of his second-in-command, the notorious James Wilkinson to supplant him. On top of it all, Wayne suffered from bouts of severe gout that left him bedridden for days at a time. The fact that Wayne's legion was able to stick together for as long as it did depended on luck as much as any other factor.

For more general information, I'd check out this old post, with responses by me and /u/RioAbajo, and let me know if you have any follow-up questions! edited to actually include the referred post