The amount that Planned Parenthood receives from abortion fees is somewhat beside the point.
Prior to the time of the Roe v Wade decision, advocates for legalized abortion based their argument on the need for an alternative to the 'back alley butchers' who were the sole source available to victims of rape and incest. Abortions would then be safe and, as was the case, rare. Eventually, the arguments included situations in which the mother was in danger of death.
This argument gained support from many who expected that legal abortions would be quite limited in number. Did anyone, at that time, expect that forty years later, the count would be nearly 50 million? I doubt it.
What happened is that as the economics of the procedure became understood, a new industry sprang up. A cash cow of unprecedented proportions was seen to be emerging. With so much money flowing from its udder, that cow was making millionaires out of people who, a few years earlier, would have been prosecuted for the same actions.
As the primary referral source of 'customers' to the practitioners, Planned Parenthood gets its cut of the fees generated.