Hosting a webserver is vastly different than realtime control of a surface. If your web server hiccups for a second and the page takes slightly longer to load, most people wouldn't notice.
If your console suddenly became unresponsive, and adjustments made took 2-3 seconds to happen, suddenly that console would be considered a piece of shit and replaced with something that doesn't do that.
The limits they put in place are there to make sure that the resources of the console are NEVER taxed beyond the worst case scenario for remote control. That way, it works all the time.
Just a few short years ago, the concept of 10 tablets being able to control a single mixer was an insane concept. Now that it's more mainstream, that limitation seems a little lower than some may like. As time goes on, I'm sure manufacturers will see the demand for more devices being able to connect, and will produce hardware that can do more.