Here is a textbook example of how courts view legal malpractice cases.  Their view does not necessarily comport with the reality of litigation.  In Katz v. Herzfeld & Rubin  the court holds:

"In support of the motion to dismiss, the defendant submitted evidence establishing that the acts of malpractice alleged in the complaint, including the defendant’s refusal to pursue a highly questionable claim for exaggerated lost earnings damages based on the injured plaintiff’s life expectancy and its purported delay in retaining an economist to evaluate the lost earnings claim, did not cause any alleged reduction in the amount of the monetary settlement reached in the underlying personal injury action. The defendant demonstrated that the plaintiffs discharged it and hired new counsel five months before they settled the underlying action. Under these circumstances, the defendant established that its actions did not proximately cause the plaintiffs’ alleged damages, and that subsequent counsel had a sufficient opportunity to protect the plaintiffs’ rights by pursuing any remedies it deemed appropriate on their behalf (see Ramcharan v Pariser, 20 AD3d 556; Perks v Lauto & Garabedian, 306 AD2d 261; Albin v Pearson, 289 AD2d 272; Kozmol v Law Firm of Allen L. Rothenberg, 241 AD2d 484). Thus, the Supreme Court properly dismissed the legal malpractice cause of action.

Things to note:  "A settlement of the underlying claim does not preclude a subsequent action for legal malpractice where the settlement was effectively compelled by the mistakes of counsel (see Tortura v Sullivan Papain Block McGrath & Cannavo, P.C., 21 AD3d 1082.

The Court determined the quality  of plaintiff’s evidence on this CPLR 3211 motion, when it found that their personal injury claims were "highly questionable"  and "exaggerated."

Lastly, as anyone who has looked for a new attorney when the case is underway, trying to get an attorney to take over a case after or close to the note of issue is often impossible.  The court is very optimistic when it says that subsequent counsel had the opportunity, to protect plaintiff.