The guilty verdict against Bill Cosby was hailed by some as long overdue.

Not just because his victim, Andrea Constand, first reported that he had sexually assaulted her 13 years ago, but also because, as a lawyer for other Cosby accusers put it, “women were finally believed.”

Getting there required surmounting significant obstacles: a victim who waited a year to report the crime and gave two different dates for the attack, a prosecutor who declined to bring the case, a new district attorney who raced against the statute of limitations and, finally, a first trial in which the jury could not agree.

That was before a series of revelations that caused a seismic shift in public awareness of sexual assault by powerful men. And this is after. But those who know the legal system best say the verdict is not the bellwether that many would like. Criminal convictions in sexual misconduct cases where the victims and the accused knew each other will remain exceedingly hard to get.

Neither Harvey Weinstein, the former Hollywood mogul, nor Russell Simmons, the music producer, has faced criminal charges, despite investigations into allegations against each of them. James Toback, a film director who has been accused by scores of women of sexual misconduct over decades, will likely never face arrest because the statute of limitations has expired.