Eve online - Skill Farming was NEVER EVAR profitable. srsly.
TL;DW provided in first part. Second part was created before the TLDW version and goes into why exactly SP farms were never evar profitable.
basically, there's two ways you can look at SP farming
(1) as a way to never pay CCP a damn cent
(2) get a 50% off deal on 12 months omega + 6000 plex in small quarterly installments
it's not going to be 'free' because you still need to make sure your SP farmer gets 150,000 unallocated a month, plus needs 333m isk (currently) for that initially injection.
but, yeah, those are the hard cold numbers for both options.