The threat of an argument is often stronger then the argument itself.
UNCERTAINTY
Most attorneys are risk adverse, and will over emphasize the risk of losing a case. The risk associated with litigation can be even higher if the attorney does not know how to conduct a proper case analysis. Sometimes to make matters worse an attorney will over emphasize the opinion of opposing counsel by giving them too much deference. All these fears associated with the case will disappear once the issue has been adjudicated on and the threat of the argument is gone. For this reason the threat of an argument may be stronger than the argument itself.
UNPREPAREDNESS
It is almost impossible to be fully prepared for trial, and attorneys will have different levels of preparedness. As a case gets closer to trial most attorneys will feel unprepared. There are a number of reasons attorneys feel unprepared including: a lack of experience, expert witnesses are unavailable, the attorney isn't prepared for trial, etc. Even if opposing counsel is prepared they will often want to make last minute changes, and engage in late discovery. Most the time attorneys do not want to litigate these issues.
CONCLUSION
Although the threat of an argument is often stronger than the argument itself this is not always true. Plaintiff verdicts are on average much higher than a settlement. It is also important not to assume opposing counsel under emphasized their case. You must rely on your own independent analysis of the case to know when opposing counsel has over valued their case.