The American Revolution started in 1763

Delanceyplace.com has a  selection from The American West by Anne M. Butler and Michael J. Lansing:

Adventurous citizens in the thirteen original British colonies in America had long gone west in search of new land. It was a continuation of the original American dream, but the French and Native Americans had long impeded that expansion. So, at the at the end of Britain's victory over the French and the Native Americans in the French and Indian War in 1763, these British colonists had expected to continue their westward migration. Instead, in a pronouncement that shocked them, the King prohibited the colonists from buying or settling these western lands, sparking an anger that finally erupted in the American Revolution itself, when the insult of taxes to pay for the French and Indian War was added to the injury of the prohibition on settlement:

And We do hereby strictly forbid, on Pain of our Displeasure all of our loving subjects from making any Purchases or Settlements whatever, or taking Possession of any of the Lands above reserved."
                                                The Royal Proclamation, 7 October 1763

In the colonies, it was the small farmers and settlers who felt the weight of the King's order, prohibited, as individuals, to purchase land, negotiate trade, or simply steal land from Native people. Now, according to King George III, these people were ever to remain British colonials, setting aside the lure of western settlement, land-grabbing, and maverick politics, always so common in an unregulated territory. These were all galling bits of news for the Americans, fresh from defending the King's turf during the grueling seven years of the French and Indian War. From 1756 to 1763, that conflict had revealed the ineptness of the British military when confronted with guerilla-like fighters on foreign soil.
After several discouraging years for the British colonies, the French, in a series of defeats, revealed they were, indeed, vulnerable. Indian warriors reassessed their positions and backed away from their French alliances, several groups joining the British forces. Then, in an improbable move that undid the French, James Wolfe and his soldiers scaled a shear cliff of rock outside Quebec, Canada, stunning the forces of Marquis de Montcalm on the Plains of Abraham, a broad field high above the old city of Quebec.
After this bloody fight in Canada, there were other diplomatic details to be concluded, among them significant issues concerning the balance of power in Europe, but, in North America, the French loss rekindled the western fever of British colonists. With the defeat of King George's enemies in North America, formalized through the Treaty of Paris of 1763, those who had endured the bitter years and fought for the distant monarch anticipated appreciation and generosity, especially in the tangible form of western lands. In addition, disgruntled colonists muttered about other pronouncements from the King, ones that regulated negotiations for native land and granted religious freedom to the French Catholics, living to the north in Quebec. Loyal British subjects certainly had not bargained for political considerations for their recent foes, the 'heathen' Natives and the hated French of Quebec and the Ohio Valley.
Given the tumultuous circumstances, the great distance between the governor and the governed, the long festering ill-will of the French, and Indian resistance, it must have seemed a sound strategy to offer these latter two groups some balm, something to deflect their simmering anger over the outcome of the French and Indian War. Perhaps King George could reduce his problems in North America by good faith action, promising Native Americans a halt to the British settlers flooding into the western regions of the thirteen colonies and quelling the restlessness of New France, chagrined that its mother country had utterly failed to protect the Canadian colonies.
Of course, the proclamation also was centered directly on the King's more immediate colonial interests. Drawing some boundaries for the colonists appeared to be the sensible way for the mother country to keep watch over her frequently unruly subjects, whose wandering ways complicated the collection of taxes for the crown. The suggested displeasure of King George, should his American subjects choose to ignore this proclamation, proved slight compared to the surliness that flared among the colonists, who grumbled the document conveyed more rights to 'savages and Papists' than to British subjects.
Poor King George, with his imaginary boundary line that arced across the Appalachians from Nova Scotia to Florida, and his nod to the French and their staunchest native allies who managed to ignite the fires of unity among the notoriously fragmented and feuding colonists from Savannah to Boston, from Charleston to New York City. Thus, King George, or, more correctly, Great Britain's Privy Council, succeeded in what no patriot voice had yet managed and pointed the cantankerous colonists toward common banners: their distaste for the French, scorn for the Indians, anger toward Great Britain, and lust for more land.

Rico says anger and lust; never fails...