Unfortunately some TVs pester you when they can't get internet access, or will even attempt to connect to any open WiFi networks in range.
Some have offline ads or can't boot straight to an input, too.
Then there's Amazon trialing having Amazon-powered TVs automatically connecting to any Alexa devices and using them to gain internet access.
I'm not saying OPs suggestion is the best one, for most TVs, what you suggest works very well. But it's good to have more options, particularly as the market continues to get more and more locked-down.
Even aside from all that, if you could replace the controller board, that would open up other possibilities - potentially adding DisplayPort to a TV, for example. Or retrofitting FreeSync if the panel supports it. Or even just plain TV repair without having to pay through the nose for a part you can only get from Samsung/LG/Sony/etc.
Just not feasible though. Smart TVs have everything in an integrated line, from the screen controller, down to the external ports. It's like saying "Hey, I just want to take the North Bridge out of my motherboard because I don't use the features". Not gonna happen.
Now, in an alternate universe, if somebody went down this route and made replacement parts to remove all the cruft, you'd essentially be buying an entire new TV. There is no cost savings there. Buy a monitor, and hook up whatever smart shit you want at that point.
Unfortunately some TVs pester you when they can't get internet access, or will even attempt to connect to any open WiFi networks in range.
Some have offline ads or can't boot straight to an input, too.
Then there's Amazon trialing having Amazon-powered TVs automatically connecting to any Alexa devices and using them to gain internet access.
I'm not saying OPs suggestion is the best one, for most TVs, what you suggest works very well. But it's good to have more options, particularly as the market continues to get more and more locked-down.
Even aside from all that, if you could replace the controller board, that would open up other possibilities - potentially adding DisplayPort to a TV, for example. Or retrofitting FreeSync if the panel supports it. Or even just plain TV repair without having to pay through the nose for a part you can only get from Samsung/LG/Sony/etc.
Just not feasible though. Smart TVs have everything in an integrated line, from the screen controller, down to the external ports. It's like saying "Hey, I just want to take the North Bridge out of my motherboard because I don't use the features". Not gonna happen.
Now, in an alternate universe, if somebody went down this route and made replacement parts to remove all the cruft, you'd essentially be buying an entire new TV. There is no cost savings there. Buy a monitor, and hook up whatever smart shit you want at that point.
We gotta get in there and disconnect the antennas
But I've heard of a few models that don't function at all until connected.... yikes