I love how people are so jaded when America is on the right side of a conflict for the first time in a long time. America is supplying aid to a country to defend itself from an imperialistic invader, it gets to get rid of its expiring weapon stocks by donating them to a country that is decimating their biggest military rival.
This arrangement is win win win for everyone involved.
The Raytheons and Boeings of the world would much rather the US be buying big ticket items like ships, fighter aircraft, and AMRAAMs than lower margin items like Javelins and 155mm artillery ammunition.
Military systems go through a constant cycle of acquisition, usage, upgrades, retirement, and replacement. Some systems, like big aircraft with relatively undemanding flight and usage profiles, can be kept operational and upgraded for a long time. Others, like missiles, have shorter lifetimes and are less worth refurbishing and upgrading after a point. A certain proportion of what the US has donated was going to have to be retired, disposed of, and replaced in the next few years anyway.
And with the current Supreme Court, I expect that opening the designs for competitive bidding would be considered a "taking", so it would be a matter of time before the changes get reversed or weakened.