The only thing I can think of that would prevent easy copying in the SaaS world would be to have most or all of your data generated by users, and then doggedly protecting that data from scraping, and/or hiding it behind a login.
Otherwise, if your business relies on scraping other peoples data and then presenting a nice UI around that, it could just as easily be replicated by others (no moat, as we're saying nowadays).
Of course, much like the niche chemical salesman, maybe the ideal scraping business would be to find such a niche that is small enough that other people wouldn't find it worthwhile to replicate your SaaS.