Well, we don't actually know that the next administration won't support them any. We assume they won't because of Trump's attitude to Ukraine, but the republicans have been somewhat divided over the issue, and Trump just does whatever he randomly feels like, and sending more military aid does benefit the MIC that can pay politicians, so it possible, if unlikely, that they'd get some support from them. There's also the possibility of support from Europe or elsewhere in the world. Finally, while a Ukrainian loss without foreign support seems quite likely, the pace of Russia's advances and resource expendature are such that a win for them is no longer likely to be "annex Ukraine or make it a puppet rump state", but more "take a strip of land close to the current occupation line", in which case a stronger Ukraine has a better negotiating position and so may be able to give up less.