What's the biggest hurtle to companies, which currently accept Bitcoin, accepting lightning network payments?
It really depends on whether you’re using a 3rd party service provider or if you are running the Bitcoin infrastructure yourself. There are tools like BTCPayServer that make it possible for you to host a sophisticated Bitcoin/Lightning setup from home pretty easily. That being said Lightning nodes require active management, unlike Bitcoin Core nodes.
I’d say pick your flavor. Maybe test with a provider first and then spend time and resources moving it to your own infrastructure if it makes sense? It’s really dependent on your technical profile imo.