I think it's too much for any company.
In this world of constant upgrading, do you really want a hopefully long term big purchase like a TV, to outlive it's usefulness early?
How many versions of "Smart TV" have all the manufacturers gone through already? My Bluray player has Viera Cast, (the first version, not the second) and can't be upgraded due to hardware limitations, and certainly doesn't do the latest Viera Connect.
Samsung, LG, Vizio, all the same, different names.
Sure, Apple will get it "right" the first time.
But will they guarantee the hardware in that TV to be fully compatible with any and all possible future ideas, upgrades, etc. for the next 5-10 years?
Does your 1st Gen iPhone do iOS5?
Give me the $100 dollar box any day...