Sure they can afford to scrap bad boards. Damn, it's the best thing for them to do. Initially.
Fuck the cost, think of the cost of their first deliveries not being on time against that, and cancelled orders.
Get the initial couple of dozen or so units out of the door ASAP, gain the kudos for that, then relax a bit and test chips once they have that milestone achieved.
IF they get 50 perfectly working rigs in customers hands (literally since they are collected), get some good feedback... the lion's share of orders are october delivery so they'll have more time. Then they can test and not waste components.
Just curious, do you think they should test assembled miners before shipping? Like at least turning them on and running them for a few minutes? Or ship them asap and let customers find out if they work? The latter also saves them time and money.
This isnt only about wasting components, automated testing of those chips will if anything, speed up production of functional miners. It takes so much longer to assemble (and test!) a complete miner based on a bad chip than it does to do chip level testing.