Paul,
Much of the direct aid provided by the US to the Ukraine came from stocks which were already in Europe for the purpose of fighting the USSR. The Bradley's which the US committed to providing generally fall under this category. Although they still have "value", they were already paid for a long time ago. Much of the military aid that provided early on fell in this category. Newer equipment such as the HIMARS, ATACMS and others cannot be lumped into this category. You may not remember but the US kept saying that the Russians were coming before the war started and warned the Ukraine. Other countries did not, for example, in France, the President fired his Minister of Defense (or similar) for not interpreting the intelligence correctly.
Politically, in the lower house of Congress, providing aid to the Ukraine has proven unpopular and based on the comments made by one of the candidates regarding NATO it would appear to me that he would be willing to let the Ukraine go to Putin along with a few other European countries.
Although in terms of the gross amount, the US has provided the largest share of aid, other countries have provided more as a percentage of their GDP, including one of the countries (Germany) which one of the candidates has been critical of in the past:
https://www.statista.com/statistics/1303450/bilateral-aid-to-ukraine-in-a-percent-of-donor-gdp/The summer offensive did not achieve what they were hoping to and a few days they lost one of the key cities (at least symbolically) that they had retaken. Personally, I would like to see them win but realistically I no longer think that it is possible unless something drastically changes within Russia.
This has been a coming to Jesus moment for the US and other countries, not only in Europe but Asia as well. It was estimated that if NATO had committed all of their air assets they might have been able to establish air superiority over portions of the Ukraine for a maximum of two weeks. Probably not enough to win the war. The RAF is stretched thin with too many commitments around the world; good training for the aircrews but rough on the equipment. The US strategy has always been to establish air superiority first which meant having plenty of missiles and bombs but as we have been, in a near peer scenario, that might not be possible.
Although the Ukraine needs the 155 mm shells, they US has come to realize that it needs them as well. In broader terms, the US military has come to realize that how they fight the next war might be different from what they had expected. For example, the Air Force relies on the Navy Growlers for electronic warfare, something they gave up after the F111 was retired. One of the first things sent to Europe when the war started were 6 Growlers to collect electronic data (ELINT). Further, the Navy is starting to become a larger part of the budget as they try maintain and improve their capabilities with an eye on China. The new frigate program is an example of that; they are also thinking about fighting in smaller, more dispersed groups. Drones will also play an important part as well. Canada is getting new ships, so are Australia and Japan. And we will need their help if Taiwan becomes a thing.