The Seven Years War pitted the imperial powers of France and Britain against each other. Several years before the end of the war, the two European countries' global dominance declined as mounting expenses of maintaining colonies exceeded the revenues. Both countries were battling on multiple fronts, exacerbating the economic difficulties of overexpansion.
The battlefront in the American colonies proved to strain further the limited resources of both nations. With the signing of the Treaty of Paris in 1763, the war came to a close. Britain gained extensive new territories through the agreement. While the gain may have been viewed as a positive for the British, it further strained Great Britain's economy. It brought forth a whole new set of problems, including conflicts with native tribes. Many of the native tribes had friendly relations with the French and many of the colonists.
The imposition of restricting colonists to not go beyond the western frontier west of the Ohio River Valley alienated the American colonists and British merchants who saw the western frontier as an underdeveloped economic gold mine. This did not sit well with American colonists, who believed they were unfairly penalized for a war between two European powers. Though the American colonists had strained relations with both countries, the Americans preferred trade over war. They believed they could leverage the competition between France and Britain to the American colonies' economic advantage.
The Seven Years War crippled Britain economically, and to recoup their losses, Britain turned to impose several fees, tariffs, and taxes on the American colonists. By 1763, second-generation colonists did not necessarily identify with Britain as their home country. The British's heavy-handed tactics in reigning in protests of the fees combined with the loss of national identity with Britain led several of the colonists to conclude it was time either the British respected American colonists' sovereignty through negotiation or the face a revolution.
First-generation settlers continued to identify with British nationalism and the American colonies as an extension of the British monarchy. As the American colonies' population began to grow from immigration from other countries and homegrown population growth, many in the first generation began to recognize a shift in the balance of power between the Americans and British. It was becoming apparent that the British would not sustain in the long-term rule over the American colonies.
It is not so much that the first generation were alienated from the home country as it was that the economic reality was that America was becoming self-sufficient. The need for British subsidies and British management of resources quickly became an obstacle to the inevitable expansion of America west and America becoming a self-sufficient governing nation-state. These realizations by loyal British subjects were one unintended consequence of the Seven Years War.