As these frontier companies have been boasting, writing software is now a negligible cost because the LLM can do it.
IOW, no, their software can't be a moat, because, according to their own arguments, you can use their LLM to trivially clone their software.
Perhaps, but what you can't clone is familiarity, polish, integration, and network effects. These companies desperately need a moat, and so for example all the new additions to Claude's web interface are becoming the products that the vast majority of people will use and be locked into (if it goes according to their plan).
I'm not sure what network effects even means in the context of llm selection.
good luck.