Why is this important? The HIMARS missiles, PATRIOT batteries and missiles, Javelins, artillery s s, and on and on that we donate have to be replaced at our expense. Of course this also potentially risks our own readiness to meet our various global defense treaty commitments because the replacements can't be manufactured quickly enough.
Oh, I agree that it was always going to be this way. General Mark Milley has been warning for like a year now that it would be extremely difficult to eject Russia military from Ukraine which is why he seemed to want Ukraine to start negotiating a long time ago.
Both sides are taking big casualties including Ukraine, even if they don't want to admit precisely how big.