'Reasonable time' is the phrase arrived at by our elected representatives, not the TV vendors. Five years is not the mean time before failure, either. Nothing is stopping you from making a case to Trading Standards if your TV fails after seven years - five years is merely a figure that the vendors are using, and what they offer has no effect on your statutory rights. However, what is 'reasonable' depends upon the product.
If you really have an issue with it, write to your MP.
People don't see themselves as being 'nickle and dimed' when the television they can buy for £500 today is far bigger and of higher resolution than a set the same money would have bought them a few years back. Oh, and don't suggest the general public are 'stupid' - it betrays your ignorance.
>What I really want to know is "How is the user going to fix this problem when they don't even have a PC any more?"
Well, if the product proves to be 'not fit for the purpose for which it was sold', the onus is on the retailer to sort the issue out for the buyer