Bluray is far from a waste. It's everywhere now. Xbox One's have it, too, which means Sony gets a profit for every Xbox One sold. Granted, it's probably not even $5 per console, but the One has sold a few million consoles. Even if Sony made just a dollar off of each sale, that's a few million dollars in profit.
And as for the 'nice TV' thing - The majority of people in at least America, and I'd guess majority of people in quite a few other countries, own a decent TV now that -does- work well with Bluray. So it pays off quite well.
Bluray should definitely not be considered a bad investment by Sony.