What is the name of your state (only U.S. law)? California. What would be a reason why a plaintiff's lawyer would file an initial complaint without the sworn statement line under penalty of perjury being anywhere in the document?
What would be the reason?
Let me ask you what makes you believe that California requires such a sworn statement? If your thinking is that in your state all civil complaints must be verified under oath - either by the attorney for the plaintiff or if appearing without an attorney then by the plaintiff - then you are mistaken.
What California does require is that all pleadings, petition, motions, notice of motions, etc., etc., shall be signed by at least one attorney of record, or if the party is appearing pro se then by the party. (See Cal. CCP Sections 128.7 and 446) (Although an affidavit may be used to verify a pleading (Cal CPP 2009) unless it is a special proceeding in which the pleader intends to rely on some particular rule of law, statute, etc. that requires such verification (2015.5) it is NOT mandatory.)
However, this discussion is for naught. It is entirely meaningless as to whether or not the complaint is actually verified. It is without significance! Why?
I'll tell you why. It is because of Cal CPP Rule 128.7 - (California's adaptation of Rule 11 of the Federal Rules of Civil Procedure) which provides that any time an attorney or litigant signs, files, submits or later advocates a pleading, petition, written notice of motion, or other similar paper, THEREBY CERTIFIES to the best of the person’s knowledge, information, and belief, formed after an inquiry reasonable under the circumstances, that all of the following conditions are met:
1. It is not being submitted for any improper purpose such as to harass or to cause unnecessary delay or needless increase in the cost of litigation.
2. The claims, defenses, and other legal contentions therein are warranted by existing law or are subject to nonfrivolous argument for modification of existing law.
3. The allegations and other factual contentions contained have evidentiary support or, if specifically so identified, are likely to have evidentiary support after a reasonable opportunity for further investigation or discovery.
Although the Rule does not speak in terms of penalty of perjury violations can result in severe sanctions imposed upon the offender.