By the 1980s NATO had evolved into a US dominated organization for intimidating the USSR and it still plays that role in regard to modern Russia. Not only did NATO vastly outspend the USSR and its allies, but NATO's strategy of "Forward Defence" rather than defence in depth created a very aggressive posture so far as the Warsaw Pact was concerned. As I said, NATO provided the USA with a very cheap bulwark against the USSR, allowing it to focus much of its military spending on other areas, such as building up its fleets of aircraft carriers to project a global presence; one that the USSR did not have the resources to challenge. If the US chooses to waste trillions on defence spending that is its business, just as it is Canada's business not to follow suit.
Cites?
Your bulwark is the land that Russia, and later, the USSR, wanted to take. In the 1940s and 1950s, Russia was very aggressively looking to expand their union. It was not a matter of the US using Europe. Russia wanted more. With the introduction of long range bombers, intercontinental ballistic missiles, etc., the game changed.
Whether NATO is of any value today is a moot point. Any nation that wishes to remain a member must pay their dues. If you do not wish to pay anymore, or feel that NATO's role is not relevant to the modern age, withdraw. There is nothing forcing nations to remain as members.
Like any club, should you wish to be a member, you pay your dues. If you want to quit, pull out.