There's plenty of low end Blu-Ray players for $50, most of them are dumb at that price point. But they will generally be slower as they are built to the price, so they use slower drives and processors but they will be adequate.
Check out your local Walmart and be amazed as they probably have a half dozen at that price.
As for making them smart, well, it comes about because the CPU power is there - when you've got a more powerful CPU, adding smart services is trivial - it costs practically nothing and for a lot of people, it's a value add. If you don't want it, don't use it - but the faster drives and speed might make it more worthwhile to spend the extra $50 and not use the smart features.