Sam decided to refine the bloodline. Because, him doing some refining can be explained with some sort of excuses like meridian cleansing or other kinds of treatment to the body ailments they are naturally born with.
But if he creates a cultivation technique and some of them spreads it, the powerhouses will be high on his heels.
Although, he was not afraid of them, he should avoid the unnecessary trouble. After all, no powerhouse believe that Sam truly created a cultivation technique and attach the presence of cultivation technique with some inheritance or treasure, which would lead him to trouble.
Even if he is under protection now, that is not going to last for long.
One more reason is, even if he is responsible for these guys for now, that is only temporary, for them to waste his time and create a whole new cultivation technique, it is not entirely beneficial to him in the long run and they would be the one benefiting more than him.
