Analyze the following argument concerning intellectual property law:
[S1] The traditional justification for intellectual property rights rests on a utilitarian premise: granting temporary monopolies incentivizes innovation that ultimately benefits the public. [S2] Yet, as the digital economy expands, the rigid application of copyright law to software interfaces has produced the opposite effect, stifling competition by creating artificial monopolies over industry standards. [S3] While some legal scholars propose resolving this tension by treating software interfaces as uncopyrightable "methods of operation," this approach fails to address the unique communicative function of code. [S4] Instead, copyright frameworks must be legislatively restructured to grant broad interoperability exemptions for all interface protocols, recognizing that such interfaces function essentially as shared languages rather than mere tools. [S5] Only through such legislative reform can the law restore the historical balance between rewarding individual creators and preserving the collaborative nature of technological development.
Identify the sentence label (e.g., S1, S2) that marks the author's explicit main point.
Answer: S4 / s4 / [S4] / [s4] / Sentence 4 / Sentence S4