Many offer upgraded options that they charge money for. But I think the main reason they like to do web based is to make the system easy to setup for remote acc

Many offer upgraded options that they charge money for. But I think the main reason they like to do web based is to make the system easy to setup for remote access. 99% of their customers are not going to want to figure out how to open a port on their router so they can control it with an app while away. And then of course you have to deal with dynamic IP addresses and other edge cases.