I'm going to take a guess and say that Philips used third-party software for these TVs. Since they don't own the software, and since the software is probably non-free (that's free as in freedom), the existing software probably can't be updated... at least not legally. Philips could replace the encryption software altogether, but they simply don't want to. After all, it's easier for them to make these customers buy a new TV then do actual work, and it's more profitable, since customers are new forced to buy a new TV or use an external devices.
In other news, I'm thinking about getting a smart TV. Of course, by "getting a smart TV", I mean getting equipment that will allow me to hook my laptop up to a TV.Â I get plenty of updates for my laptop. If program "A" stops receiving updates, I'll switch to program "B".