Its actually pretty profitable.
Not for ships though.
Remember that thanks to CCP not updating the adjusted prices ( see Huge discrepancies in industry tax application ) , you can build some items in Jita with (almost) no manufacturing tax.
And some of those items have a 20% margin on the direct sell. Just saying …
Also people are trying to pump&dump so don’t go to fast or you’ll buy your mats on the pump.