i don't see any bullet holes or shrapnel marks, do you?

did they scramble its signal to bring it down? is iran running drone jammers we don't know about?

if they got lucky and it's not that, it's still really bad for the US, iran will definitely get a lot out of stripping this thing down and seeing what makes it tick

otoh, if they DO have effective drone jamming... the US military makes up for the shortfall of trained pilots (a problem of expense and scarcity of talent) by using these things en masse... if that's no longer reliable then strike missions will increasingly have to be flown by pilots we don't have, at cost and maximum risk to loss of assets and loss of life (because you never send one piloted aircraft, but you nearly always send one and only one drone)