You're right, but software does find itself in a non-competitive environment thanks to a sea of intellectual property laws that benefit incumbents. That external party is ever-present, and no doubt implied in discussions here.
Unless you mean copyright / trade-secrets specifically, then IP laws don't really help SaaS that much.
For example take Google Workspace - email, calendar, docs. Google has no particular patents for those, and I've never heard about startups in this area not getting traction because of IP troubles.
Same goes with Jira, or Github, or Slack, or AWS S3 - all of those don't have particularly many patents and in fact there are plenty of alternatives, self-hosted or otherwise. People still pay for them happily.
