Why are startup security products better than those from security pioneers?

Got chance to POC new age security products from startups and so far, I loved the UI/UX and usability. Have been using security tools from pioneers like Trellix, Symantec but always have issues with lag and non-user friendly UI. Any thoughts?

Edit - I'm talking about UI and features. Not sure about scalability.

age cybersecurity edit far features lag non poc products security security products security tools startup startups symantec talking thoughts tools trellix usability