Some really misleading numbers in that article.
There is no way in hell the average net profit on a flip is anywhere near 40% or 60%.
It looks like they are just subtracting the prior sale from the last sale with no consideration for repairs.
I try to be in at 75-80% of the after repair value (ARV) and then you have closing costs. My best flip was an $80,000 net on a $245,000 SP. The house cost $100,000 with about $55,000 in repairs. The rest was commish and seller paid closing costs. If you are netting 20% you are doing really well.