Taking tanks as an example, the delay/staggering in getting them into Ukraine this summer was because in most cases they had been decommissioned by the finishing countries and so had to be refurbished first. The frankly hilarious videos of choppers left behind in Afghanistan falling out of the sky give you an example of the usefulness of decommissioned tech, without the refurbs Ukrainians would’ve been killed using them.
On planes and missiles, real life isn’t Call of Duty, they need to be trained or else you’re giving £bn of paper weights. On F16s, the US had been saying for months they’re ready to start training and Ukraine needs to put up the pilots…
Ukraine put up pilots for Gripen training and it’s a matter of time before they get some, but again, Saab and Flygvappnet need to ensure Sukhoi won’t be bringing a questionable clone to market next year.