Please explain to us how you think that litecoin is more profitable than bitcoin?
50% is such a nice even rounded number, that I'd like to know how you mathematically reached it.

That website does not compare BTC to litecoin.

I used a litecoin calculator and found that it earns less coin and less USD per GPU.

I am NOT using "room to grow" speculation.
Speculation is guessing.  Guessing is not fact.
Lets talk about today, not the hypothetical future.